From bb23335b5fd29fb1d63e99b8f9eb32c5f11b4405 Mon Sep 17 00:00:00 2001
From: Emmanuele Bassi <ebassi@gnome.org>
Date: Wed, 9 Dec 2015 14:26:28 +0000
Subject: [PATCH] Add a configuration option for deciding the Cogl drivers to
 use

Using environment variables only is not convenient for all platforms,
and in some cases it's beneficial to decide the default driver when
building Clutter. Cogl already has a similar configuration switch, and
since Clutter is overriding the default Cogl behaviour, it should offer
the same mechanism.

https://bugzilla.gnome.org/show_bug.cgi?id=742678
---
 clutter/clutter-backend.c | 2 +-
 configure.ac              | 9 +++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/clutter/clutter-backend.c b/clutter/clutter-backend.c
index 62f33ec0b..71710e395 100644
--- a/clutter/clutter-backend.c
+++ b/clutter/clutter-backend.c
@@ -386,7 +386,7 @@ clutter_backend_real_create_context (ClutterBackend  *backend,
   int i;
 
   if (allowed_drivers == NULL)
-    allowed_drivers = "*";
+    allowed_drivers = CLUTTER_DRIVERS;
 
   allow_any = strstr (allowed_drivers, "*") != NULL;
 
diff --git a/configure.ac b/configure.ac
index 985dc1b83..e32f5dd71 100644
--- a/configure.ac
+++ b/configure.ac
@@ -585,6 +585,13 @@ dnl other tools such as glib-mkenums and gir-scanner don't end up
 dnl using the define also.
 AC_DEFINE([COGL_ENABLE_EXPERIMENTAL_2_0_API], [1], [Can use Cogl 2.0 API internally])
 
+AC_ARG_WITH([default-drivers],
+            [AS_HELP_STRING([--with-default-drivers=DRIVER], [Comma-separated list of Cogl drivers to use])],
+            [clutter_drivers=$withval],
+            [clutter_drivers="*"])
+
+AC_DEFINE_UNQUOTED([CLUTTER_DRIVERS], ["$clutter_drivers"], [List of Cogl drivers])
+
 dnl strip leading spaces
 CLUTTER_BACKENDS=${CLUTTER_BACKENDS#* }
 AC_SUBST(CLUTTER_BACKENDS)
@@ -1285,6 +1292,8 @@ else
 echo "        Input backends: ${CLUTTER_INPUT_BACKENDS} (WARNING: Experimental backends enabled)"
 fi
 
+echo "        Cogl drivers: $clutter_drivers"
+
 if test "x$SUPPORT_X11" = "x1"; then
 echo ""
 echo "     - X11 backend options:"