[qt4] Improved to use zlib, libtiff, libpng, libmng, libjpeg, openssl and nas from "system" when possible

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 - 2007 The OpenSDE Project
+# Copyright (C) 2006 - 2008 The OpenSDE Project
 # Copyright (C) 2004 - 2006 The T2 SDE Project
 # Copyright (C) 1998 - 2004 Clifford Wolf
 #
@@ -37,6 +37,19 @@ EOT
 
 confopt="-prefix $root/$prefix -bindir $root/$bindir -libdir $root/$libdir -docdir $root/$docdir -headerdir $root/$includedir -plugindir $root/$libdir/$pkg/plugins -datadir $root/$datadir -translationdir $root/$datadir/translations -sysconfdir $root/$sysconfdir -v"
 
+# What may come from system?
+for x in zlib libtiff libpng libmng libjpeg openssl nas; do
+	if pkginstalled $x; then
+		case "$x" in
+		openssl)	y='-openssl' ;;
+		nas)		y='-system-nas-sound' ;;
+		*)		y="-system-$x" ;;
+		esac
+
+		var_append confopt ' ' "$y"
+	fi
+done
+
 # Disable debug information, this interferes with qt4 suffix. With debug
 # enabled we end up with 2 sets of executables. One with qt4 suffix and
 # one without. As a result we end up with shared files with qt3.