diff -r 376921880a7f -r 5099a34747c4 configure
--- a/configure	Sun Mar 31 18:29:06 2024 +0200
+++ b/configure	Sun Apr 07 11:26:38 2024 +0200
@@ -1,40 +1,53 @@
 #!/bin/sh
 
-
-PREFIX=/usr
-EPREFIX=$PREFIX
+# create temporary directory
+TEMP_DIR=".tmp-`uname -n`"
+rm -Rf "$TEMP_DIR"
+if mkdir -p "$TEMP_DIR"; then
+    :
+else
+    echo "Cannot create tmp dir $TEMP_DIR"
+    echo "Abort"
+    exit 1
+fi
+touch "$TEMP_DIR/options"
+touch "$TEMP_DIR/features"
 
-BINDIR=
-SBINDIR=
-LIBDIR=
-LIBEXECDIR=
-DATADIR=
-SYSCONFDIR=
-SHAREDSTATEDIR=
-LOCALSTATEDIR=
-INCLUDEDIR=
-INFODIR=
-MANDIR=
+# define standard variables
+# also define standard prefix (this is where we will search for config.site)
+prefix=/usr
+exec_prefix=
+bindir=
+sbindir=
+libdir=
+libexecdir=
+datarootdir=
+datadir=
+sysconfdir=
+sharedstatedir=
+localstatedir=
+runstatedir=
+includedir=
+infodir=
+localedir=
+mandir=
 
-OS=`uname -s`
-OS_VERSION=`uname -r`
-
-TEMP_DIR=".tmp-`uname -n`"
-mkdir -p $TEMP_DIR
-if [ $? -ne 0 ]; then
-	echo "Cannot create tmp dir"
-	echo "Abort"
-fi
-touch $TEMP_DIR/options
-touch $TEMP_DIR/features
+# custom variables
 
 # features
 
+# clean abort
+abort_configure()
+{
+    rm -Rf "$TEMP_DIR"
+    exit 1
+}
+
 # help text
 printhelp()
 {
-	echo "Usage: $0 [OPTIONS]..."
-	cat << __EOF__
+    echo "Usage: $0 [OPTIONS]..."
+    cat << __EOF__
 Installation directories:
   --prefix=PREFIX         path prefix for architecture-independent files
                           [/usr]
@@ -47,497 +60,482 @@
   --sysconfdir=DIR        system configuration files [PREFIX/etc]
   --sharedstatedir=DIR    modifiable architecture-independent data [PREFIX/com]
   --localstatedir=DIR     modifiable single-machine data [PREFIX/var]
+  --runstatedir=DIR       run-time variable data [LOCALSTATEDIR/run]
   --libdir=DIR            object code libraries [EPREFIX/lib]
   --includedir=DIR        C header files [PREFIX/include]
   --datarootdir=DIR       read-only arch.-independent data root [PREFIX/share]
   --datadir=DIR           read-only architecture-independent data [DATAROOTDIR]
   --infodir=DIR           info documentation [DATAROOTDIR/info]
   --mandir=DIR            man documentation [DATAROOTDIR/man]
+  --localedir=DIR         locale-dependent data [DATAROOTDIR/locale]
 
 Options:
+  --debug                 add extra compile flags for debug builds
+  --release               add extra compile flags for release builds
   --toolkit=(gtk4|gtk3|gtk2|gtk2legacy|qt5|qt4|motif)
 
 __EOF__
 }
 
 #
-# parse arguments 
+# parse arguments
 #
-for ARG in $@
+BUILD_TYPE="default"
+for ARG in "$@"
 do
     case "$ARG" in
-		"--prefix="*)         PREFIX=${ARG#--prefix=} ;;
-		"--exec-prefix="*)    EPREFIX=${ARG#--exec-prefix=} ;;
-		"--bindir="*)         BINDIR=${ARG#----bindir=} ;;
-		"--sbindir="*)        SBINDIR=${ARG#--sbindir=} ;;
-		"--libdir="*)         LIBDIR=${ARG#--libdir=} ;;
-		"--libexecdir="*)     LIBEXECDIR=${ARG#--libexecdir=} ;;
-		"--datadir="*)        DATADIR=${ARG#--datadir=} ;;
-		"--sysconfdir="*)     SYSCONFDIR=${ARG#--sysconfdir=} ;;
-		"--sharedstatedir="*) SHAREDSTATEDIR=${ARG#--sharedstatedir=} ;;
-		"--localstatedir="*)  LOCALSTATEDIR=${ARG#--localstatedir=} ;;
-		"--includedir="*)     INCLUDEDIR=${ARG#--includedir=} ;;
-		"--infodir="*)        INFODIR=${ARG#--infodir=} ;;
-		"--mandir"*)          MANDIR=${ARG#--mandir} ;;
-		"--help"*) printhelp; exit 1 ;;
-    	"--toolkit="*) OPT_TOOLKIT=${ARG#--toolkit=} ;;
-		"-"*) echo "unknown option: $ARG"; exit 1 ;;
-	esac
+        "--prefix="*)         prefix=${ARG#--prefix=} ;;
+        "--exec-prefix="*)    exec_prefix=${ARG#--exec-prefix=} ;;
+        "--bindir="*)         bindir=${ARG#----bindir=} ;;
+        "--sbindir="*)        sbindir=${ARG#--sbindir=} ;;
+        "--libdir="*)         libdir=${ARG#--libdir=} ;;
+        "--libexecdir="*)     libexecdir=${ARG#--libexecdir=} ;;
+        "--datarootdir="*)    datarootdir=${ARG#--datarootdir=} ;;
+        "--datadir="*)        datadir=${ARG#--datadir=} ;;
+        "--sysconfdir="*)     sysconfdir=${ARG#--sysconfdir=} ;;
+        "--sharedstatedir="*) sharedstatedir=${ARG#--sharedstatedir=} ;;
+        "--localstatedir="*)  localstatedir=${ARG#--localstatedir=} ;;
+        "--includedir="*)     includedir=${ARG#--includedir=} ;;
+        "--infodir="*)        infodir=${ARG#--infodir=} ;;
+        "--mandir"*)          mandir=${ARG#--mandir} ;;
+        "--localedir"*)       localedir=${ARG#--localedir} ;;
+        "--help"*) printhelp; abort_configure ;;
+        "--debug")           BUILD_TYPE="debug" ;;
+        "--release")         BUILD_TYPE="release" ;;
+        "--toolkit="*) OPT_TOOLKIT=${ARG#--toolkit=} ;;
+        "-"*) echo "unknown option: $ARG"; abort_configure ;;
+    esac
 done
 
-# set dir variables
-if [ -z "$BINDIR" ]; then
-	BINDIR=$EPREFIX/bin
-fi
-if [ -z "$SBINDIR" ]; then
-	SBINDIR=$EPREFIX/sbin
-fi
-if [ -z "$LIBDIR" ]; then
-	LIBDIR=$EPREFIX/lib
-fi
-if [ -z "$LIBEXEC" ]; then
-	LIBEXECDIR=$EPREFIX/libexec
-fi
-if [ -z "$DATADIR" ]; then
-	DATADIR=$PREFIX/share
-fi
-if [ -z "$SYSCONFDIR" ]; then
-	SYSCONFDIR=$PREFIX/etc
-fi
-if [ -z "$SHAREDSTATEDIR" ]; then
-	SHAREDSTATEDIR=$PREFIX/com
-fi
-if [ -z "$LOCALSTATEDIR" ]; then
-	LOCALSTATEDIR=$PREFIX/var
-fi
-if [ -z "$INCLUDEDIR" ]; then
-	INCLUDEDIR=$PREFIX/include
-fi
-if [ -z "$INFODIR" ]; then
-	INFODIR=$PREFIX/info
-fi
-if [ -z "$MANDIR" ]; then
-	MANDIR=$PREFIX/man
+
+
+# set defaults for dir variables
+: ${exec_prefix:="$prefix"}
+: ${bindir:='${exec_prefix}/bin'}
+: ${sbindir:='${exec_prefix}/sbin'}
+: ${libdir:='${exec_prefix}/lib'}
+: ${libexecdir:='${exec_prefix}/libexec'}
+: ${datarootdir:='${prefix}/share'}
+: ${datadir:='${datarootdir}'}
+: ${sysconfdir:='${prefix}/etc'}
+: ${sharedstatedir:='${prefix}/com'}
+: ${localstatedir:='${prefix}/var'}
+: ${runstatedir:='${localstatedir}/run'}
+: ${includedir:='${prefix}/include'}
+: ${infodir:='${datarootdir}/info'}
+: ${mandir:='${datarootdir}/man'}
+: ${localedir:='${datarootdir}/locale'}
+
+# check if a config.site exists and load it
+if [ -n "$CONFIG_SITE" ]; then
+    # CONFIG_SITE may contain space separated file names
+    for cs in $CONFIG_SITE; do
+        printf "loading defaults from $cs... "
+        . "$cs"
+        echo ok
+    done
+elif [ -f "$prefix/share/config.site" ]; then
+    printf "loading site defaults... "
+    . "$prefix/share/config.site"
+    echo ok
+elif [ -f "$prefix/etc/config.site" ]; then
+    printf "loading site defaults... "
+    . "$prefix/etc/config.site"
+    echo ok
 fi
 
-which pkg-config > /dev/null
-if [ $? -eq 0 ]; then
-    PKG_CONFIG=pkg-config
-else
-    PKG_CONFIG=false
-fi
+# Test for availability of pkg-config
+PKG_CONFIG=`command -v pkg-config`
+: ${PKG_CONFIG:="false"}
 
 # Simple uname based platform detection
 # $PLATFORM is used for platform dependent dependency selection
+OS=`uname -s`
+OS_VERSION=`uname -r`
 printf "detect platform... "
-if [ $OS = SunOS ]; then
+if [ "$OS" = "SunOS" ]; then
     PLATFORM="solaris sunos unix svr4"
-fi
-if [ $OS = Linux ]; then
+elif [ "$OS" = "Linux" ]; then
     PLATFORM="linux unix"
-fi
-if [ $OS = FreeBSD ]; then
+elif [ "$OS" = "FreeBSD" ]; then
     PLATFORM="freebsd bsd unix"
-fi
-if [ $OS = Darwin ]; then
+elif [ "$OS" = "OpenBSD" ]; then
+    PLATFORM="openbsd bsd unix"
+elif [ "$OS" = "NetBSD" ]; then
+    PLATFORM="netbsd bsd unix"
+elif [ "$OS" = "Darwin" ]; then
     PLATFORM="macos osx bsd unix"
-fi
-echo $OS | grep "MINGW" > /dev/null
-if [ $? -eq 0 ]; then
+elif echo "$OS" | grep -i "MINGW" > /dev/null; then
     PLATFORM="windows mingw"
 fi
-
-if [ -z "$PLATFORM" ]; then
-    PLATFORM="unix"
-fi
+: ${PLATFORM:="unix"}
 
-for p in $PLATFORM
-do
-	PLATFORM_NAME=$p
-	break
-done
-echo $PLATFORM_NAME
+PLATFORM_NAME=`echo "$PLATFORM" | cut -f1 -d' ' -`
+echo "$PLATFORM_NAME"
 
 isplatform()
 {
     for p in $PLATFORM
     do
-        if [ $p = $1 ]; then
+        if [ "$p" = "$1" ]; then
             return 0
         fi
     done
     return 1
 }
-isnotplatform()
+notisplatform()
 {
     for p in $PLATFORM
     do
-        if [ $p = $1 ]; then
+        if [ "$p" = "$1" ]; then
+            return 1
+        fi
+    done
+    return 0
+}
+istoolchain()
+{
+    for t in $TOOLCHAIN
+    do
+        if [ "$t" = "$1" ]; then
+            return 0
+        fi
+    done
+    return 1
+}
+notistoolchain()
+{
+    for t in $TOOLCHAIN
+    do
+        if [ "$t" = "$1" ]; then
             return 1
         fi
     done
     return 0
 }
 
-# generate config.mk and config.h
-cat > $TEMP_DIR/config.mk << __EOF__
-#
-# config.mk generated by configure
-#
 
-# general vars
-
-PREFIX=$PREFIX
-EPREFIX=$EPREFIX
-
-BINDIR=$BINDIR
-SBINDIR=$SBINDIR
-LIBDIR=$LIBDIR
-LIBEXECDIR=$LIBEXECDIR
-DATADIR=$DATADIR
-SYSCONFDIR=$SYSCONFDIR
-SHAREDSTATEDIR=$SHAREDSTATEDIR
-LOCALSTATEDIR=$LOCALSTATEDIR
-INCLUDEDIR=$INCLUDEDIR
-INFODIR=$INFODIR
-MANDIR=$MANDIR
-
+# generate vars.mk
+cat > "$TEMP_DIR/vars.mk" << __EOF__
+prefix=$prefix
+exec_prefix=$exec_prefix
+bindir=$bindir
+sbindir=$sbindir
+libdir=$libdir
+libexecdir=$libexecdir
+datarootdir=$datarootdir
+datadir=$datadir
+sysconfdir=$sysconfdir
+sharedstatedir=$sharedstatedir
+localstatedir=$localstatedir
+runstatedir=$runstatedir
+includedir=$includedir
+infodir=$infodir
+mandir=$mandir
+localedir=$localedir
 __EOF__
 
-echo > $TEMP_DIR/make.mk
-
-ENV_CFLAGS=$CFLAGS
-ENV_LDFLAGS=$LDFLAGS
-ENV_CXXFLAGS=$CXXFLAGS
-
-# Toolchain detection
-# this will insert make vars to config.mk
+# toolchain detection utilities
 . make/toolchain.sh
 
-# add user specified flags to config.mk
-echo >> $TEMP_DIR/config.mk
-if [ ! -z "${ENV_CFLAGS}" ]; then
-    echo "CFLAGS += $ENV_CFLAGS" >> $TEMP_DIR/config.mk
-fi
-if [ ! -z "${ENV_CXXFLAGS}" ]; then
-    echo "CXXFLAGS += $ENV_CXXFLAGS" >> $TEMP_DIR/config.mk
-fi
-if [ ! -z "${ENV_LDFLAGS}" ]; then
-    echo "LDFLAGS += $ENV_LDFLAGS" >> $TEMP_DIR/config.mk
-fi
-
 #
 # DEPENDENCIES
 #
 
-dependency_qt4()
+# check languages
+lang_c=
+lang_cpp=
+if detect_c_compiler ; then
+    lang_c=1
+fi
+
+# create buffer for make variables required by dependencies
+echo > "$TEMP_DIR/make.mk"
+
+test_pkg_config()
 {
-    printf "checking for qt4... "
-    # dependency qt4 
-    while true
-    do
-        qmake-qt4 -o - /dev/null | grep DEFINES\  > /dev/null
-        if [ $? -eq 0 ]; then
-            CFLAGS="$CFLAGS `qmake-qt4 -o - /dev/null | grep DEFINES\ `"
-        else
-            break
-        fi
-        qmake-qt4 -o - /dev/null | grep INCPATH\  > /dev/null
-        if [ $? -eq 0 ]; then
-            CFLAGS="$CFLAGS `qmake-qt4 -o - /dev/null | grep INCPATH\ `"
-        else
-            break
-        fi
-         > /dev/null
-        if [ $? -eq 0 ]; then
-            LDFLAGS="$LDFLAGS ``"
-        else
-            break
-        fi
-        which qmake-qt4 > /dev/null
-        if [ $? -ne 0 ]; then
-        	break
-        fi
-		echo yes
-        return 0
-    done
-	
-	echo no
-	return 1
+    if "$PKG_CONFIG" --exists "$1" ; then :
+    else return 1 ; fi
+    if [ -z "$2" ] || "$PKG_CONFIG" --atleast-version="$2" "$1" ; then :
+    else return 1 ; fi
+    if [ -z "$3" ] || "$PKG_CONFIG" --exact-version="$3" "$1" ; then :
+    else return 1 ; fi
+    if [ -z "$4" ] || "$PKG_CONFIG" --max-version="$4" "$1" ; then :
+    else return 1 ; fi
+    return 0
 }
-dependency_gtk2legacy()
+
+print_check_msg()
 {
-    printf "checking for gtk2legacy... "
-    # dependency gtk2legacy 
+    if [ -z "$1" ]; then
+        shift
+        printf "$@"
+    fi
+}
+
+dependency_error_gtk2legacy()
+{
+    print_check_msg "$dep_checked_gtk2legacy" "checking for gtk2legacy... "
+    # dependency gtk2legacy
     while true
     do
         if [ -z "$PKG_CONFIG" ]; then
-        	break
-        fi
-		$PKG_CONFIG gtk+-2.0
-        if [ $? -ne 0 ] ; then
             break
         fi
-        CFLAGS="$CFLAGS `$PKG_CONFIG --cflags gtk+-2.0`"
-        LDFLAGS="$LDFLAGS `$PKG_CONFIG --libs gtk+-2.0`"
-        CFLAGS="$CFLAGS -DUI_GTK2 -DUI_GTK2LEGACY"    
-        LDFLAGS="$LDFLAGS -lpthread"    
-		echo yes
-        return 0
-    done
-	
-	echo no
-	return 1
-}
-dependency_qt5()
-{
-    printf "checking for qt5... "
-    # dependency qt5 
-    while true
-    do
-        qmake-qt5 -o - /dev/null | grep DEFINES\  > /dev/null
-        if [ $? -eq 0 ]; then
-            CFLAGS="$CFLAGS `qmake-qt5 -o - /dev/null | grep DEFINES\ `"
+        if test_pkg_config "gtk+-2.0" "" "" "" ; then
+            TEMP_CFLAGS="$TEMP_CFLAGS `"$PKG_CONFIG" --cflags gtk+-2.0`"
+            TEMP_LDFLAGS="$TEMP_LDFLAGS `"$PKG_CONFIG" --libs gtk+-2.0`"
         else
             break
         fi
-        qmake-qt5 -o - /dev/null | grep INCPATH\  > /dev/null
-        if [ $? -eq 0 ]; then
-            CFLAGS="$CFLAGS `qmake-qt5 -o - /dev/null | grep INCPATH\ `"
-        else
+        TEMP_CFLAGS="$TEMP_CFLAGS -DUI_GTK2 -DUI_GTK2LEGACY"
+        TEMP_LDFLAGS="$TEMP_LDFLAGS -lpthread"
+        print_check_msg "$dep_checked_gtk2legacy" "yes\n"
+        dep_checked_gtk2legacy=1
+        return 1
+    done
+
+    print_check_msg "$dep_checked_gtk2legacy" "no\n"
+    dep_checked_gtk2legacy=1
+    return 0
+}
+dependency_error_gtk2()
+{
+    print_check_msg "$dep_checked_gtk2" "checking for gtk2... "
+    # dependency gtk2
+    while true
+    do
+        if [ -z "$PKG_CONFIG" ]; then
             break
         fi
-         > /dev/null
-        if [ $? -eq 0 ]; then
-            LDFLAGS="$LDFLAGS ``"
+        if pkg-config --atleast-version=2.20 gtk+-2.0 > /dev/null ; then
+            :
         else
             break
         fi
-        which qmake-qt5 > /dev/null
-        if [ $? -ne 0 ]; then
-        	break
+        if test_pkg_config "gtk+-2.0" "" "" "" ; then
+            TEMP_CFLAGS="$TEMP_CFLAGS `"$PKG_CONFIG" --cflags gtk+-2.0`"
+            TEMP_LDFLAGS="$TEMP_LDFLAGS `"$PKG_CONFIG" --libs gtk+-2.0`"
+        else
+            break
         fi
-		echo yes
-        return 0
+        TEMP_CFLAGS="$TEMP_CFLAGS -DUI_GTK2"
+        TEMP_LDFLAGS="$TEMP_LDFLAGS -lpthread"
+        print_check_msg "$dep_checked_gtk2" "yes\n"
+        dep_checked_gtk2=1
+        return 1
     done
-	
-	echo no
-	return 1
+
+    print_check_msg "$dep_checked_gtk2" "no\n"
+    dep_checked_gtk2=1
+    return 0
 }
-dependency_gtk2()
+dependency_error_gtk3()
 {
-    printf "checking for gtk2... "
-    # dependency gtk2 
+    print_check_msg "$dep_checked_gtk3" "checking for gtk3... "
+    # dependency gtk3
     while true
     do
         if [ -z "$PKG_CONFIG" ]; then
-        	break
+            break
         fi
-		$PKG_CONFIG gtk+-2.0
-        if [ $? -ne 0 ] ; then
+        if test_pkg_config "gtk+-3.0" "" "" "" ; then
+            TEMP_CFLAGS="$TEMP_CFLAGS `"$PKG_CONFIG" --cflags gtk+-3.0`"
+            TEMP_LDFLAGS="$TEMP_LDFLAGS `"$PKG_CONFIG" --libs gtk+-3.0`"
+        else
             break
         fi
-        CFLAGS="$CFLAGS `$PKG_CONFIG --cflags gtk+-2.0`"
-        LDFLAGS="$LDFLAGS `$PKG_CONFIG --libs gtk+-2.0`"
-        CFLAGS="$CFLAGS -DUI_GTK2"    
-        LDFLAGS="$LDFLAGS -lpthread"    
-        pkg-config --atleast-version=2.20 gtk+-2.0 > /dev/null
-        if [ $? -ne 0 ]; then
-        	break
-        fi
-		echo yes
-        return 0
+        TEMP_CFLAGS="$TEMP_CFLAGS -DUI_GTK3"
+        TEMP_LDFLAGS="$TEMP_LDFLAGS -lpthread"
+        print_check_msg "$dep_checked_gtk3" "yes\n"
+        dep_checked_gtk3=1
+        return 1
     done
-	
-	echo no
-	return 1
+
+    print_check_msg "$dep_checked_gtk3" "no\n"
+    dep_checked_gtk3=1
+    return 0
 }
-dependency_gtk3()
+dependency_error_gtk4()
 {
-    printf "checking for gtk3... "
-    # dependency gtk3 
-    while true
-    do
-        if [ -z "$PKG_CONFIG" ]; then
-        	break
-        fi
-		$PKG_CONFIG gtk+-3.0
-        if [ $? -ne 0 ] ; then
-            break
-        fi
-        CFLAGS="$CFLAGS `$PKG_CONFIG --cflags gtk+-3.0`"
-        LDFLAGS="$LDFLAGS `$PKG_CONFIG --libs gtk+-3.0`"
-        CFLAGS="$CFLAGS -DUI_GTK3"    
-        LDFLAGS="$LDFLAGS -lpthread"    
-		echo yes
-        return 0
-    done
-	
-	echo no
-	return 1
-}
-dependency_gtk4()
-{
-    printf "checking for gtk4... "
-    # dependency gtk4 
+    print_check_msg "$dep_checked_gtk4" "checking for gtk4... "
+    # dependency gtk4
     while true
     do
         if [ -z "$PKG_CONFIG" ]; then
-        	break
+            break
         fi
-		$PKG_CONFIG gtk+-4.0
-        if [ $? -ne 0 ] ; then
+        if test_pkg_config "gtk+-4.0" "" "" "" ; then
+            TEMP_CFLAGS="$TEMP_CFLAGS `"$PKG_CONFIG" --cflags gtk+-4.0`"
+            TEMP_LDFLAGS="$TEMP_LDFLAGS `"$PKG_CONFIG" --libs gtk+-4.0`"
+        else
             break
         fi
-        CFLAGS="$CFLAGS `$PKG_CONFIG --cflags gtk+-4.0`"
-        LDFLAGS="$LDFLAGS `$PKG_CONFIG --libs gtk+-4.0`"
-        CFLAGS="$CFLAGS -DUI_GTK3"    
-        LDFLAGS="$LDFLAGS -lpthread"    
-		echo yes
-        return 0
+        TEMP_CFLAGS="$TEMP_CFLAGS -DUI_GTK3"
+        TEMP_LDFLAGS="$TEMP_LDFLAGS -lpthread"
+        print_check_msg "$dep_checked_gtk4" "yes\n"
+        dep_checked_gtk4=1
+        return 1
     done
-	
-	echo no
-	return 1
+
+    print_check_msg "$dep_checked_gtk4" "no\n"
+    dep_checked_gtk4=1
+    return 0
 }
-dependency_motif()
+dependency_error_motif()
 {
-    printf "checking for motif... "
+    print_check_msg "$dep_checked_motif" "checking for motif... "
     # dependency motif platform="bsd"
     while true
     do
-    	if isnotplatform "bsd"; then
+        if notisplatform "bsd"; then
             break
         fi
-        CFLAGS="$CFLAGS -DUI_MOTIF -I/usr/local/include/X11"    
-        LDFLAGS="$LDFLAGS -lXm -lXt -lX11 -lpthread"    
-		echo yes
-        return 0
+        TEMP_CFLAGS="$TEMP_CFLAGS -DUI_MOTIF -I/usr/local/include/X11"
+        TEMP_LDFLAGS="$TEMP_LDFLAGS -lXm -lXt -lX11 -lpthread"
+        print_check_msg "$dep_checked_motif" "yes\n"
+        dep_checked_motif=1
+        return 1
     done
-	
-    # dependency motif 
+
+    # dependency motif
     while true
     do
-        CFLAGS="$CFLAGS -DUI_MOTIF"    
-        LDFLAGS="$LDFLAGS -lXm -lXt -lX11 -lpthread"    
-		echo yes
-        return 0
+        TEMP_CFLAGS="$TEMP_CFLAGS -DUI_MOTIF"
+        TEMP_LDFLAGS="$TEMP_LDFLAGS -lXm -lXt -lX11 -lpthread"
+        print_check_msg "$dep_checked_motif" "yes\n"
+        dep_checked_motif=1
+        return 1
     done
-	
-	echo no
-	return 1
+
+    print_check_msg "$dep_checked_motif" "no\n"
+    dep_checked_motif=1
+    return 0
 }
-dependency_winui()
+dependency_error_cocoa()
 {
-    printf "checking for winui... "
+    print_check_msg "$dep_checked_cocoa" "checking for cocoa... "
+    # dependency cocoa platform="macos"
+    while true
+    do
+        if notisplatform "macos"; then
+            break
+        fi
+        TEMP_CFLAGS="$TEMP_CFLAGS -DUI_COCOA"
+        TEMP_LDFLAGS="$TEMP_LDFLAGS -lobjc -framework Cocoa"
+        print_check_msg "$dep_checked_cocoa" "yes\n"
+        dep_checked_cocoa=1
+        return 1
+    done
+
+    print_check_msg "$dep_checked_cocoa" "no\n"
+    dep_checked_cocoa=1
+    return 0
+}
+dependency_error_winui()
+{
+    print_check_msg "$dep_checked_winui" "checking for winui... "
     # dependency winui platform="windows"
     while true
     do
-    	if isnotplatform "windows"; then
+        if notisplatform "windows"; then
             break
         fi
-        CFLAGS="$CFLAGS -DUI_WINUI"    
-		echo yes
-        return 0
+        TEMP_CFLAGS="$TEMP_CFLAGS -DUI_WINUI"
+        print_check_msg "$dep_checked_winui" "yes\n"
+        dep_checked_winui=1
+        return 1
     done
-	
-	echo no
-	return 1
+
+    print_check_msg "$dep_checked_winui" "no\n"
+    dep_checked_winui=1
+    return 0
 }
-dependency_cocoa()
-{
-    printf "checking for cocoa... "
-    # dependency cocoa platform="macos"
-    while true
-    do
-    	if isnotplatform "macos"; then
-            break
-        fi
-        CFLAGS="$CFLAGS -DUI_COCOA"    
-        LDFLAGS="$LDFLAGS -lobjc -framework Cocoa"    
-		echo yes
-        return 0
-    done
-	
-	echo no
-	return 1
-}
+
+# start collecting dependency information
+echo > "$TEMP_DIR/flags.mk"
 
 DEPENDENCIES_FAILED=
 ERROR=0
-# general dependencies
-CFLAGS=
-LDFLAGS=
+# unnamed dependencies
+TEMP_CFLAGS=
+TEMP_CXXFLAGS=
+TEMP_LDFLAGS=
 while true
 do
-    if isnotplatform "macos"; then
+    while true
+    do
+        if [ -z "$lang_c" ] ; then
+            ERROR=1
+            break
+        fi
+
+        break
+    done
+    break
+done
+while true
+do
+    if notisplatform "macos"; then
         break
     fi
     while true
     do
-        
-		cat >> $TEMP_DIR/make.mk << __EOF__
+
+        cat >> "$TEMP_DIR/make.mk" << __EOF__
 OBJ_EXT = .o
 LIB_EXT = .a
 PACKAGE_SCRIPT = package_osx.sh
-
 __EOF__
-        
         break
     done
-    
     break
 done
 while true
 do
-    if isnotplatform "unix"; then
+    if notisplatform "unix"; then
         break
     fi
-    if isplatform "macos"; then
+    if isplatform "macos" || istoolchain "macos"; then
         break
     fi
     while true
     do
-        
-		cat >> $TEMP_DIR/make.mk << __EOF__
+
+        cat >> "$TEMP_DIR/make.mk" << __EOF__
 OBJ_EXT = .o
 LIB_EXT = .a
 PACKAGE_SCRIPT = package_unix.sh
-
 __EOF__
-        
         break
     done
-    
     break
 done
 while true
 do
-    if isnotplatform "bsd"; then
+    if notisplatform "bsd"; then
         break
     fi
     while true
     do
-        
-        CFLAGS="$CFLAGS -I/usr/local/include"    
-        LDFLAGS="$LDFLAGS -L/usr/local/lib"    
-        
+
+        TEMP_CFLAGS="$TEMP_CFLAGS -I/usr/local/include"
+        TEMP_LDFLAGS="$TEMP_LDFLAGS -L/usr/local/lib"
         break
     done
-    
     break
 done
 
-# add general dependency flags to config.mk
-echo >> $TEMP_DIR/config.mk
-if [ ! -z "${CFLAGS}" ]; then
-    echo "CFLAGS += $CFLAGS" >> $TEMP_DIR/config.mk
+# add general dependency flags to flags.mk
+echo "# general flags" >> "$TEMP_DIR/flags.mk"
+if [ -n "${TEMP_CFLAGS}" ] && [ -n "$lang_c" ]; then
+    echo "CFLAGS += $TEMP_CFLAGS" >> "$TEMP_DIR/flags.mk"
 fi
-if [ ! -z "${CXXFLAGS}" ]; then
-    echo "CXXFLAGS += $CXXFLAGS" >> $TEMP_DIR/config.mk
+if [ -n "${TEMP_CXXFLAGS}" ] && [ -n "$lang_cpp" ]; then
+    echo "CXXFLAGS += $TEMP_CXXFLAGS" >> "$TEMP_DIR/flags.mk"
 fi
-if [ ! -z "${LDFLAGS}" ]; then
-    echo "LDFLAGS += $LDFLAGS" >> $TEMP_DIR/config.mk
+if [ -n "${TEMP_LDFLAGS}" ]; then
+    echo "LDFLAGS += $TEMP_LDFLAGS" >> "$TEMP_DIR/flags.mk"
 fi
 
 #
@@ -545,274 +543,292 @@
 #
 checkopt_toolkit_gtk4()
 {
-	VERR=0
-	dependency_gtk4
-	if [ $? -ne 0 ]; then
-		VERR=1
-	fi
-	if [ $VERR -ne 0 ]; then
-		return 1
-	fi
-	cat >> $TEMP_DIR/make.mk << __EOF__
+    VERR=0
+    if dependency_error_gtk4 ; then
+        VERR=1
+    fi
+    if [ $VERR -ne 0 ]; then
+        return 1
+    fi
+    cat >> "$TEMP_DIR/make.mk" << __EOF__
 TOOLKIT = gtk
 GTKOBJ = draw_cairo.o
-
 __EOF__
-	return 0
+    return 0
 }
 checkopt_toolkit_gtk3()
 {
-	VERR=0
-	dependency_gtk3
-	if [ $? -ne 0 ]; then
-		VERR=1
-	fi
-	if [ $VERR -ne 0 ]; then
-		return 1
-	fi
-	cat >> $TEMP_DIR/make.mk << __EOF__
+    VERR=0
+    if dependency_error_gtk3 ; then
+        VERR=1
+    fi
+    if [ $VERR -ne 0 ]; then
+        return 1
+    fi
+    cat >> "$TEMP_DIR/make.mk" << __EOF__
 TOOLKIT = gtk
 GTKOBJ = draw_cairo.o
-
 __EOF__
-	return 0
+    return 0
 }
 checkopt_toolkit_gtk2()
 {
-	VERR=0
-	dependency_gtk2
-	if [ $? -ne 0 ]; then
-		VERR=1
-	fi
-	if [ $VERR -ne 0 ]; then
-		return 1
-	fi
-	cat >> $TEMP_DIR/make.mk << __EOF__
+    VERR=0
+    if dependency_error_gtk2 ; then
+        VERR=1
+    fi
+    if [ $VERR -ne 0 ]; then
+        return 1
+    fi
+    cat >> "$TEMP_DIR/make.mk" << __EOF__
 TOOLKIT = gtk
 GTKOBJ = draw_cairo.o
-
 __EOF__
-	return 0
+    return 0
 }
 checkopt_toolkit_gtk2legacy()
 {
-	VERR=0
-	dependency_gtk2legacy
-	if [ $? -ne 0 ]; then
-		VERR=1
-	fi
-	if [ $VERR -ne 0 ]; then
-		return 1
-	fi
-	cat >> $TEMP_DIR/make.mk << __EOF__
+    VERR=0
+    if dependency_error_gtk2legacy ; then
+        VERR=1
+    fi
+    if [ $VERR -ne 0 ]; then
+        return 1
+    fi
+    cat >> "$TEMP_DIR/make.mk" << __EOF__
 TOOLKIT = gtk
 GTKOBJ = draw_gdk.o
-
 __EOF__
-	return 0
+    return 0
 }
 checkopt_toolkit_qt5()
 {
-	VERR=0
-	dependency_qt5
-	if [ $? -ne 0 ]; then
-		VERR=1
-	fi
-	if [ $VERR -ne 0 ]; then
-		return 1
-	fi
-	cat >> $TEMP_DIR/make.mk << __EOF__
+    VERR=0
+    if dependency_error_qt5 ; then
+        VERR=1
+    fi
+    if [ $VERR -ne 0 ]; then
+        return 1
+    fi
+    cat >> "$TEMP_DIR/make.mk" << __EOF__
 TOOLKIT = qt
 LD = $(CXX)
-
 __EOF__
-	return 0
+    return 0
 }
 checkopt_toolkit_qt4()
 {
-	VERR=0
-	dependency_qt4
-	if [ $? -ne 0 ]; then
-		VERR=1
-	fi
-	if [ $VERR -ne 0 ]; then
-		return 1
-	fi
-	cat >> $TEMP_DIR/make.mk << __EOF__
+    VERR=0
+    if dependency_error_qt4 ; then
+        VERR=1
+    fi
+    if [ $VERR -ne 0 ]; then
+        return 1
+    fi
+    cat >> "$TEMP_DIR/make.mk" << __EOF__
 TOOLKIT = qt
 LD = $(CXX)
-
 __EOF__
-	return 0
+    return 0
 }
 checkopt_toolkit_motif()
 {
-	VERR=0
-	dependency_motif
-	if [ $? -ne 0 ]; then
-		VERR=1
-	fi
-	if [ $VERR -ne 0 ]; then
-		return 1
-	fi
-	cat >> $TEMP_DIR/make.mk << __EOF__
+    VERR=0
+    if dependency_error_motif ; then
+        VERR=1
+    fi
+    if [ $VERR -ne 0 ]; then
+        return 1
+    fi
+    cat >> "$TEMP_DIR/make.mk" << __EOF__
 TOOLKIT = motif
-
 __EOF__
-	return 0
+    return 0
 }
 
 #
 # TARGETS
 #
-CFLAGS=
-CXXFLAGS=
-LDFLAGS=
 
-# Target: tk
-CFLAGS=
-LDFLAGS=
-CXXFLAGS=
+echo >> "$TEMP_DIR/flags.mk"
+echo "configuring target: tk"
+echo "# flags for target tk" >> "$TEMP_DIR/flags.mk"
+TEMP_CFLAGS=
+TEMP_CXXFLAGS=
+TEMP_LDFLAGS=
 
 
 # Features
 
 # Option: --toolkit
-if [ -z $OPT_TOOLKIT ]; then
-	SAVED_ERROR=$ERROR
-	SAVED_DEPENDENCIES_FAILED=$DEPENDENCIES_FAILED
-	ERROR=0
-	while true
-	do
-		if isplatform "windows"; then
-		checkopt_toolkit_winui
-		if [ $? -eq 0 ]; then
-			echo "  toolkit: winui" >> $TEMP_DIR/options
-			ERROR=0
-			break
-		fi
-		fi
-		if isplatform "macos"; then
-		checkopt_toolkit_cocoa
-		if [ $? -eq 0 ]; then
-			echo "  toolkit: cocoa" >> $TEMP_DIR/options
-			ERROR=0
-			break
-		fi
-		fi
-		checkopt_toolkit_gtk3
-		if [ $? -eq 0 ]; then
-			echo "  toolkit: gtk3" >> $TEMP_DIR/options
-			ERROR=0
-			break
-		fi
-		checkopt_toolkit_qt5
-		if [ $? -eq 0 ]; then
-			echo "  toolkit: qt5" >> $TEMP_DIR/options
-			ERROR=0
-			break
-		fi
-		checkopt_toolkit_gtk2
-		if [ $? -eq 0 ]; then
-			echo "  toolkit: gtk2" >> $TEMP_DIR/options
-			ERROR=0
-			break
-		fi
-		checkopt_toolkit_qt4
-		if [ $? -eq 0 ]; then
-			echo "  toolkit: qt4" >> $TEMP_DIR/options
-			ERROR=0
-			break
-		fi
-		checkopt_toolkit_motif
-		if [ $? -eq 0 ]; then
-			echo "  toolkit: motif" >> $TEMP_DIR/options
-			ERROR=0
-			break
-		fi
-		break
-	done
-	if [ $ERROR -ne 0 ]; then
-		SAVED_ERROR=1
-	fi
-	ERROR=$SAVED_ERROR
-	DEPENDENCIES_FAILED=$SAVED_DEPENDENCIES_FAILED=
+if [ -z "$OPT_TOOLKIT" ]; then
+    echo "auto-detecting option 'toolkit'"
+    SAVED_ERROR="$ERROR"
+    SAVED_DEPENDENCIES_FAILED="$DEPENDENCIES_FAILED"
+    ERROR=1
+    while true
+    do
+        if isplatform "windows"; then
+        if checkopt_toolkit_winui ; then
+            echo "  toolkit: winui" >> "$TEMP_DIR/options"
+            ERROR=0
+            break
+        fi
+        fi
+        if isplatform "macos"; then
+        if checkopt_toolkit_cocoa ; then
+            echo "  toolkit: cocoa" >> "$TEMP_DIR/options"
+            ERROR=0
+            break
+        fi
+        fi
+        if checkopt_toolkit_gtk3 ; then
+            echo "  toolkit: gtk3" >> "$TEMP_DIR/options"
+            ERROR=0
+            break
+        fi
+        if checkopt_toolkit_qt5 ; then
+            echo "  toolkit: qt5" >> "$TEMP_DIR/options"
+            ERROR=0
+            break
+        fi
+        if checkopt_toolkit_gtk2 ; then
+            echo "  toolkit: gtk2" >> "$TEMP_DIR/options"
+            ERROR=0
+            break
+        fi
+        if checkopt_toolkit_qt4 ; then
+            echo "  toolkit: qt4" >> "$TEMP_DIR/options"
+            ERROR=0
+            break
+        fi
+        if checkopt_toolkit_motif ; then
+            echo "  toolkit: motif" >> "$TEMP_DIR/options"
+            ERROR=0
+            break
+        fi
+        break
+    done
+    if [ $ERROR -ne 0 ]; then
+        SAVED_ERROR=1
+        SAVED_DEPENDENCIES_FAILED="option 'toolkit' $SAVED_DEPENDENCIES_FAILED"
+    fi
+    ERROR="$SAVED_ERROR"
+    DEPENDENCIES_FAILED="$SAVED_DEPENDENCIES_FAILED"
 else
-	if false; then
-		false
-	elif [ $OPT_TOOLKIT = "gtk4" ]; then
-		echo "  toolkit: $OPT_TOOLKIT" >> $TEMP_DIR/options
-		checkopt_toolkit_gtk4
-		if [ $? -ne 0 ]; then
-			ERROR=1
-		fi
-	elif [ $OPT_TOOLKIT = "gtk3" ]; then
-		echo "  toolkit: $OPT_TOOLKIT" >> $TEMP_DIR/options
-		checkopt_toolkit_gtk3
-		if [ $? -ne 0 ]; then
-			ERROR=1
-		fi
-	elif [ $OPT_TOOLKIT = "gtk2" ]; then
-		echo "  toolkit: $OPT_TOOLKIT" >> $TEMP_DIR/options
-		checkopt_toolkit_gtk2
-		if [ $? -ne 0 ]; then
-			ERROR=1
-		fi
-	elif [ $OPT_TOOLKIT = "gtk2legacy" ]; then
-		echo "  toolkit: $OPT_TOOLKIT" >> $TEMP_DIR/options
-		checkopt_toolkit_gtk2legacy
-		if [ $? -ne 0 ]; then
-			ERROR=1
-		fi
-	elif [ $OPT_TOOLKIT = "qt5" ]; then
-		echo "  toolkit: $OPT_TOOLKIT" >> $TEMP_DIR/options
-		checkopt_toolkit_qt5
-		if [ $? -ne 0 ]; then
-			ERROR=1
-		fi
-	elif [ $OPT_TOOLKIT = "qt4" ]; then
-		echo "  toolkit: $OPT_TOOLKIT" >> $TEMP_DIR/options
-		checkopt_toolkit_qt4
-		if [ $? -ne 0 ]; then
-			ERROR=1
-		fi
-	elif [ $OPT_TOOLKIT = "motif" ]; then
-		echo "  toolkit: $OPT_TOOLKIT" >> $TEMP_DIR/options
-		checkopt_toolkit_motif
-		if [ $? -ne 0 ]; then
-			ERROR=1
-		fi
-	fi
+    echo "checking option toolkit = $OPT_TOOLKIT"
+    if false; then
+        false
+    elif [ "$OPT_TOOLKIT" = "gtk4" ]; then
+        echo "  toolkit: $OPT_TOOLKIT" >> $TEMP_DIR/options
+        if checkopt_toolkit_gtk4 ; then
+            :
+        else
+            ERROR=1
+            DEPENDENCIES_FAILED="option 'toolkit' $DEPENDENCIES_FAILED"
+        fi
+    elif [ "$OPT_TOOLKIT" = "gtk3" ]; then
+        echo "  toolkit: $OPT_TOOLKIT" >> $TEMP_DIR/options
+        if checkopt_toolkit_gtk3 ; then
+            :
+        else
+            ERROR=1
+            DEPENDENCIES_FAILED="option 'toolkit' $DEPENDENCIES_FAILED"
+        fi
+    elif [ "$OPT_TOOLKIT" = "gtk2" ]; then
+        echo "  toolkit: $OPT_TOOLKIT" >> $TEMP_DIR/options
+        if checkopt_toolkit_gtk2 ; then
+            :
+        else
+            ERROR=1
+            DEPENDENCIES_FAILED="option 'toolkit' $DEPENDENCIES_FAILED"
+        fi
+    elif [ "$OPT_TOOLKIT" = "gtk2legacy" ]; then
+        echo "  toolkit: $OPT_TOOLKIT" >> $TEMP_DIR/options
+        if checkopt_toolkit_gtk2legacy ; then
+            :
+        else
+            ERROR=1
+            DEPENDENCIES_FAILED="option 'toolkit' $DEPENDENCIES_FAILED"
+        fi
+    elif [ "$OPT_TOOLKIT" = "qt5" ]; then
+        echo "  toolkit: $OPT_TOOLKIT" >> $TEMP_DIR/options
+        if checkopt_toolkit_qt5 ; then
+            :
+        else
+            ERROR=1
+            DEPENDENCIES_FAILED="option 'toolkit' $DEPENDENCIES_FAILED"
+        fi
+    elif [ "$OPT_TOOLKIT" = "qt4" ]; then
+        echo "  toolkit: $OPT_TOOLKIT" >> $TEMP_DIR/options
+        if checkopt_toolkit_qt4 ; then
+            :
+        else
+            ERROR=1
+            DEPENDENCIES_FAILED="option 'toolkit' $DEPENDENCIES_FAILED"
+        fi
+    elif [ "$OPT_TOOLKIT" = "motif" ]; then
+        echo "  toolkit: $OPT_TOOLKIT" >> $TEMP_DIR/options
+        if checkopt_toolkit_motif ; then
+            :
+        else
+            ERROR=1
+            DEPENDENCIES_FAILED="option 'toolkit' $DEPENDENCIES_FAILED"
+        fi
+    fi
 fi
 
-echo >> $TEMP_DIR/config.mk
-if [ ! -z "${CFLAGS}" ]; then
-    echo "TK_CFLAGS  += $CFLAGS" >> $TEMP_DIR/config.mk
+if [ -n "${TEMP_CFLAGS}" ] && [ -n "$lang_c" ]; then
+    echo "TK_CFLAGS  += $TEMP_CFLAGS" >> "$TEMP_DIR/flags.mk"
+fi
+if [ -n "${TEMP_CXXFLAGS}" ] && [ -n "$lang_cpp" ]; then
+    echo "TK_CXXFLAGS  += $TEMP_CXXFLAGS" >> "$TEMP_DIR/flags.mk"
 fi
-if [ ! -z "${CXXFLAGS}" ]; then
-    echo "TK_CXXFLAGS += $CXXFLAGS" >> $TEMP_DIR/config.mk
+if [ "$BUILD_TYPE" = "debug" ]; then
+    if [ -n "$lang_c" ]; then
+        echo 'TK_CFLAGS += ${DEBUG_CC_FLAGS}' >> "$TEMP_DIR/flags.mk"
+    fi
+    if [ -n "$lang_cpp" ]; then
+        echo 'TK_CXXFLAGS += ${DEBUG_CXX_FLAGS}' >> "$TEMP_DIR/flags.mk"
+    fi
 fi
-if [ ! -z "${LDFLAGS}" ]; then
-    echo "TK_LDFLAGS += $LDFLAGS" >> $TEMP_DIR/config.mk
+if [ "$BUILD_TYPE" = "release" ]; then
+    if [ -n "$lang_c" ]; then
+        echo 'TK_CFLAGS += ${RELEASE_CC_FLAGS}' >> "$TEMP_DIR/flags.mk"
+    fi
+    if [ -n "$lang_cpp" ]; then
+        echo 'TK_CXXFLAGS += ${RELEASE_CXX_FLAGS}' >> "$TEMP_DIR/flags.mk"
+    fi
+fi
+if [ -n "${TEMP_LDFLAGS}" ]; then
+    echo "TK_LDFLAGS += $TEMP_LDFLAGS" >> "$TEMP_DIR/flags.mk"
 fi
 
+
+# final result
 if [ $ERROR -ne 0 ]; then
-	echo
-	echo "Error: Unresolved dependencies"
-	echo $DEPENDENCIES_FAILED
-	rm -Rf $TEMP_DIR
-	exit 1
+    echo
+    echo "Error: Unresolved dependencies"
+    echo "$DEPENDENCIES_FAILED"
+    abort_configure
 fi
 
 echo "configure finished"
 echo
 echo "Build Config:"
-echo "  PREFIX:    $PREFIX"
-echo "  TOOLCHAIN: $TOOLCHAIN_NAME"
+echo "  PREFIX:      $prefix"
+echo "  TOOLCHAIN:   $TOOLCHAIN_NAME"
 echo "Options:"
-cat $TEMP_DIR/options
+cat "$TEMP_DIR/options"
 echo
-cat $TEMP_DIR/config.mk $TEMP_DIR/make.mk > config.mk
-rm -Rf $TEMP_DIR
 
+# generate the config.mk file
+cat > "$TEMP_DIR/config.mk" << __EOF__
+#
+# config.mk generated by configure
+#
 
+__EOF__
+write_toolchain_defaults "$TEMP_DIR/toolchain.mk"
+cat "$TEMP_DIR/vars.mk" "$TEMP_DIR/toolchain.mk" "$TEMP_DIR/flags.mk" "$TEMP_DIR/make.mk" > config.mk
+rm -Rf "$TEMP_DIR"