Some changes for better use of postinstall_helpers and run_stuff_*.

Introduce run_stuff_<state>_<stage>_cmd. These are used to run
a specific command before or after the specified stage.

Introduce two new helpers: fontconfig-update.sh and mkfontxx-rebuild.sh.
The first runs fc-cache once fontconfig is installed, the second
rebuilds the fonts.dir and fonts.scale files in a directory for
a template.

Allow run_stuff_* to execute a script with any path, not just
from PKGFS_TEMPLATESDIR.

That means that now if you install GTK+ and any fonts package,
gtk-demo will work without any additional stuff.

--HG--
extra : convert_revision : c8aa7eb8d1ab958f64808af0d4c1cce8760d012e

helper-templates/fontconfig-update.sh

@@ -0,0 +1,9 @@
+#
+# This helpers runs fc-cache after fontconfig has been installed,
+# and update its list of fonts.
+#
+
+if [ -x $PKGFS_MASTERDIR/bin/fc-cache ]; then
+	$PKGFS_MASTERDIR/bin/fc-cache -f
+	[ "$?" -eq 0 ] && echo "=> Updated fontconfig fonts cache."
+fi

helper-templates/mkfontxx-rebuild.sh

@@ -0,0 +1,25 @@
+#
+# This helper rebuilds the fonts.dir and fonts.scale files in a
+# directory specified by a template.
+#
+
+[ -z "$fonts_dir" ] && return 1
+[ ! -d "$fonts_dir" ] && $mkdir_cmd -p $fonts_dir
+
+mkfontdir_cmd=$PKGFS_MASTERDIR/bin/mkfontdir
+mkfontscale_cmd=$PKGFS_MASTERDIR/bin/mkfontscale
+
+if [ -x $mkfontdir_cmd -a -x $mkfontscale_cmd ]; then
+	save_path=$(pwd -P 2>/dev/null)
+	cd $fonts_dir && $mkfontdir_cmd && $mkfontscale_cmd
+	if [ "$?" -eq 0 ]; then
+		echo "=> Updated $fonts_dir/fonts.dir."
+		echo "=> Updated $fonts_dir/fonts.scale."
+	fi
+	cd $save_path
+	unset save_path
+fi
+
+unset fonts_dir
+unset mkfontdir_cmd
+unset mkfontscale_cmd