qt4: improved to only build gui support if libx11 is effectively installed

qt/qt4/qt4.conf

@@ -2,7 +2,7 @@
 # This copyright note is auto-generated by ./scripts/Create-CopyPatch.
 #
 # Filename: package/.../qt4/qt4.conf
-# Copyright (C) 2006 - 2011 The OpenSDE Project
+# Copyright (C) 2006 - 2013 The OpenSDE Project
 # Copyright (C) 2004 - 2006 The T2 SDE Project
 # Copyright (C) 1998 - 2004 Clifford Wolf
 #
@@ -23,9 +23,16 @@ if [ "$prefix" = "usr" ]; then
 fi
 
 pkg_qt4_preconf() {
-	# fix X11 prefix to get correct pkg-config files
-	echo 'Fixing X11 prefix ...'
-	for x in $(egrep -rl X11R6 *) ; do sed -i -e "s,usr/X11R6,$(pkgprefix libx11)," $x ; done
+	if pkginstalled -f libx11; then
+		# fix X11 prefix to get correct pkg-config files
+		echo 'Fixing X11 prefix ...'
+		for x in $(egrep -rl X11R6 *) ; do sed -i -e "s,usr/X11R6,$(pkgprefix libx11)," $x ; done
+
+		QMAKE_INCDIR_X11="$( pkgprefix includedir libx11 )"
+		QMAKE_LIBDIR_X11="$( pkgprefix libdir libx11 )"
+	else
+		var_append confopt ' ' "-no-gui"
+	fi
 
 	# helping the linker to find libraries
 	QTDIR=$PWD
@@ -33,9 +40,6 @@ pkg_qt4_preconf() {
 	var_insert PATH ':' "$QTDIR/bin"
 	export QTDIR LD_LIBRARY_PATH PATH
 
-	QMAKE_INCDIR_X11="$( pkgprefix includedir libx11 )"
-	QMAKE_LIBDIR_X11="$( pkgprefix libdir libx11 )"
-
 #	cat > .qmake.vars <<-EOT
 #QMAKE_INCDIR_X11="$QMAKE_INCDIR_X11"
 #QMAKE_LIBDIR_X11="$QMAKE_LIBDIR_X11"