[gnome-shell-extensions] build: Update CSS when sass is available

[Florian Müllner <fmuellner src gnome org>]

commit d96839190df48dc75d49666bb78e5b7e32e6882c
Author: Florian Müllner <fmuellner gnome org>
Date:   Sun Feb 22 06:12:20 2015 +0100

    build: Update CSS when sass is available

 configure.ac     |    2 ++
 data/Makefile.am |   14 ++++++++++++++
 2 files changed, 16 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 8a4175d..cd6f36e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -76,6 +76,8 @@ done
 
 AC_SUBST(ENABLED_EXTENSIONS, [$ENABLED_EXTENSIONS])
 
+AC_PATH_PROG([SASS],[sass],[])
+
 dnl Please keep this sorted alphabetically
 AC_CONFIG_FILES([
   data/Makefile
diff --git a/data/Makefile.am b/data/Makefile.am
index ff70c5c..74717ac 100644
--- a/data/Makefile.am
+++ b/data/Makefile.am
@@ -24,6 +24,20 @@ theme_DATA =                                 \
        $(srcdir)/gnome-classic-high-contrast.css       \
        $(NULL)
 
+theme_sources =                                                        \
+       $(srcdir)/gnome-classic.scss                            \
+       $(srcdir)/gnome-shell-sass/_colors.scss                 \
+       $(srcdir)/gnome-shell-sass/_common.scss                 \
+       $(srcdir)/gnome-shell-sass/_drawing.scss                \
+       $(srcdir)/gnome-shell-sass/_high-contrast-colors.scss   \
+       $(NULL)
+
+%.css: %.scss $(theme_sources)
+       @if test -n "$(SASS)"; then \
+               if $(AM_V_P); then PS4= set -x; else echo "  GEN      $@"; fi; \
+               $(SASS) --sourcemap=none --update -f -q $<; \
+       fi
+
 gsettings_in_files = org.gnome.shell.extensions.classic-overrides.gschema.xml.in
 gsettings_SCHEMAS = $(gsettings_in_files:.xml.in=.xml)