--- configure.ac.old	2007-04-25 22:26:19.000000000 +0200
+++ configure.ac	2007-04-25 22:27:41.000000000 +0200
@@ -194,6 +194,9 @@
   FLUID="$fltk_prefix/bin/fluid"
   CPPFLAGS="-I$fltk_prefix/include $CPPFLAGS"
   LDFLAGS="-L$fltk_prefix/lib $LDFLAGS"
+else
+  CPPFLAGS="$(fltk-config --cxxflags) $CPPFLAGS"
+  LDFLAGS="$(fltk-config --ldflags) $LDFLAGS"
 fi
 
 AC_SUBST(FLUID)