[devhelp] build: Fix detection of GDK backend in case of multiple backends

[Frederic Peters <fpeters src gnome org>]

commit 51e150fd3a708d4451c1ff311dae0b2e42495a1a
Author: Vincent Untz <vuntz gnome org>
Date:   Mon Jul 4 14:39:22 2011 +0200

    build: Fix detection of GDK backend in case of multiple backends
    
    The GDK backend detection routine only worked in the case where GTK+ is
    built for one and only one backend.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=652999

 acinclude.m4 |   44 ++++++++++++++++++++++++++------------------
 1 files changed, 26 insertions(+), 18 deletions(-)
---
diff --git a/acinclude.m4 b/acinclude.m4
index 56aa3a2..cc47f19 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -1,24 +1,32 @@
 AC_DEFUN([IGE_PLATFORM_CHECK],[
-    gdk_target=`$PKG_CONFIG --variable=targets gtk+-3.0`
+    gdk_targets=`$PKG_CONFIG --variable=targets gtk+-3.0`
 
-    if test "x$gdk_target" = "xquartz"; then
-        AC_MSG_CHECKING([checking for Mac OS X support])
-        carbon_ok=no
-        AC_TRY_CPP([
-        #include <Carbon/Carbon.h>
-        #include <CoreServices/CoreServices.h>
-        ], carbon_ok=yes)
-        AC_MSG_RESULT($carbon_ok)
-        if test $carbon_ok = yes; then
-          IGE_PLATFORM=osx
-          IGE_PLATFORM_NAME="GTK+ OS X"
-          AC_DEFINE(HAVE_PLATFORM_OSX, 1, [whether GTK+ OS X is available])
+    IGE_PLATFORM=
+
+    for gdk_target in $gdk_targets; do
+        if test "x$gdk_target" = "xquartz"; then
+            AC_MSG_CHECKING([checking for Mac OS X support])
+            carbon_ok=no
+            AC_TRY_CPP([
+            #include <Carbon/Carbon.h>
+            #include <CoreServices/CoreServices.h>
+            ], carbon_ok=yes)
+            AC_MSG_RESULT($carbon_ok)
+            if test $carbon_ok = yes; then
+              IGE_PLATFORM=osx
+              IGE_PLATFORM_NAME="GTK+ OS X"
+              AC_DEFINE(HAVE_PLATFORM_OSX, 1, [whether GTK+ OS X is available])
+              break
+            fi
+        elif test "x$gdk_target" = "xx11"; then
+            IGE_PLATFORM=x11
+            IGE_PLATFORM_NAME="GTK+ X11"
+            AC_DEFINE(HAVE_PLATFORM_X11, 1, [whether GTK+ X11 is available])
+            break
         fi
-    elif test "x$gdk_target" = "xx11"; then
-        IGE_PLATFORM=x11
-        IGE_PLATFORM_NAME="GTK+ X11"
-        AC_DEFINE(HAVE_PLATFORM_X11, 1, [whether GTK+ X11 is available])
-    else
+    done
+
+    if test "x$IGE_PLATFORM" = "x"; then
         AC_MSG_ERROR([Could not detect the platform])
     fi