Revamp FLTK configuration -- use fltk-config. It tells us which libraries we...

Revamp FLTK configuration -- use fltk-config.  It tells us which libraries we need.  It also can tell us where to find libpng and libjpeg - either the versions built-in to fltk since 1.1.x, or else the system version if available.

src/configure.in

@@ -22,7 +22,7 @@ dnl -- checks for system services
 
 AC_HEADER_STDC
 AC_CHECK_FUNCS(strchr memcpy snprintf strcasecmp rint sqrtf)
-AC_CHECK_HEADERS(malloc.h zlib.h)
+AC_CHECK_HEADERS(malloc.h zlib.h png.h jpeglib.h)
 AC_FUNC_ALLOCA
 
 AC_PROG_CC
@@ -107,55 +107,31 @@ dnl ---------------------------------------------------------------------
 dnl             Check for FLTK
 AC_ARG_WITH(fltk, [ --with-fltk=<d>    find FLTK in -I<d>/include/FL -L<d>/lib ], with_fltk=$withval, with_fltk=/usr/local)
 
+
 if test -n "$with_fltk" && test -d "$with_fltk"; then
 	# maybe should test both $with_fltk and the include directory therein??
 	case "$with_fltk" in
 	  */) with_fltk=`expr "$with_fltk" : '\(.*\)/$'` ;;
 	esac
-	if test -f "$with_fltk/include/FL/Fl.H"; then
-	   FLTK_INC=-I$with_fltk/include
- 	elif test -f "$with_fltk/FL/Fl.H"; then
-	   FLTK_INC=-I$with_fltk
-	   if test -f "$with_fltk/png/png.h"; then
-	       FLTK_INC="-I$with_fltk -I$with_fltk/png -I$with_fltk/jpeg"
-	   fi
+	if test -x "$with_fltk/fltk-config"; then
+dnl
+	   FLTK_INC="`$with_fltk/fltk-config --use-gl --use-images --cxxflags`"
+	   FLTK_LIB="`$with_fltk/fltk-config --use-gl --use-images --ldflags`"
 	else
-	   AC_MSG_WARN("Could not find FL/Fl.H for the fltk library")
-	   with_fltk=""
+	   FLTK_INC="`$with_fltk/fltk-config --use-gl --use-images --cxxflags`"
+	   FLTK_LIB="`$with_fltk/fltk-config --use-gl --use-images --ldflags`"
 	fi
 
-
-	FLTK_LIB="-L$with_fltk/lib -lfltk"
-	if test -f "$with_fltk/lib/libfltk_gl.a" || \
-	   test -f "$with_fltk/lib/libfltk_gl.so"; then
-		FLTK_LIB="-L$with_fltk/lib -lfltk_gl -lfltk"
-	fi
 else
-	# assume the compile does -L/usr/local/lib (they don't do all....)
-	FLTK_INC=-I/usr/local/include
-	FLTK_LIB=-lfltk
-	AC_CHECK_LIB(fltk, fl_display,
-                :, AC_MSG_WARN([couldn't find fltk library]))
+dnl otherwise we'd better be able to find fltk-config in $PATH somewhere
+       FLTK_INC="`$with_fltk/fltk-config --use-gl --use-images --cxxflags`"
+       FLTK_LIB="`$with_fltk/fltk-config --use-gl --use-images --ldflags`"
 fi
 
-TEMPCPPFLAGS="$CPPFLAGS"
-CPPFLAGS="$CPPFLAGS $FLTK_INC"
-AC_CHECK_HEADERS(png.h jpeglib.h)
-CPPFLAGS="$TEMPCPPFLAGS"
-
-if test -f "$with_fltk/lib/libfltk_png.a"; then
-    FLTK_LIB="$FLTK_LIB -lfltk_png -lz"
-elif test -n "$ac_cv_header_png_h"; then
-    # hmm, if FLTK's libfltk_png.a isn't available, how do we try with pkgconfig?
-    # failing that, let's just assume it's "libpng" (not e.g. libpng12)
-    FLTK_LIB="$FLTK_LIB -lpng -lz"
+if test -z "$FLTK_INC"; then
+    AC_MSG_WARN("Couldn't find fltk-config -- is fltk 1.1.x (or later) installed?")
 fi
 
-if test -f "$with_fltk/lib/libfltk_jpeg.a"; then
-    FLTK_LIB="$FLTK_LIB -lfltk_jpeg"
-elif test -n "$ac_cv_header_jpeglib_h"; then
-    FLTK_LIB="$FLTK_LIB -ljpeg"
-fi
 
 #----------- as of partiview 0.7.04 - marx: ------------------------------------
 #we no longer support old file chooser so we deleted support for it from this file
@@ -172,22 +148,6 @@ fi
 
 
 
-
-#----------- as of partiview 0.7.04 - marx: ------------------------------------
-#we no longer support old file chooser so we deleted support for it from this file
-#in any event you should be on fltk release 1.1.x (not 2.x).
-# the library fltk_images did not exist prior to 1.1.x used to determine relase == 1.1.x
-if test -f "$with_fltk/lib/libfltk_images.a" || \
-   test -f "$with_fltk/lib/libfltk_images.so"; then
-   :
-   else
-	AC_MSG_ERROR("we do not support fltk on releases earlier than 1.1.x. you must be on fltk release 1.1.x")
-fi
-#----------end as of partiview 0.7.04 - marx: -----------------------------------
-
-
-
-
 AC_SUBST(FLTK_INC)
 AC_SUBST(FLTK_LIB)