qt4: fixed to only inject fontconfig includedir if it is installed

qt/qt4/qt4.conf

@@ -14,8 +14,6 @@
 # GNU General Public License can be found in the file COPYING.
 # --- SDE-COPYRIGHT-NOTE-END ---
 
-var_append CXX_WRAPPER_APPEND ' ' "-I$root/$(pkgprefix includedir fontconfig)"
-
 prefix="${SDECFG_PKG_QT4_PREFIX:-usr}"
 set_confopt
 if [ "$prefix" = "usr" ]; then
@@ -63,6 +61,10 @@ 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"
 
+if pkginstalled -f fontconfig; then
+	var_append CXX_WRAPPER_APPEND ' ' "-I$root/$(pkgprefix includedir fontconfig)"
+fi
+
 # What may come from system?
 for x in zlib libtiff libpng libmng libjpeg openssl nas sqlite; do
 	if pkginstalled $x; then