From 4c19b415bd75accbb13cb4a4149e6858f6f37f9c Mon Sep 17 00:00:00 2001
From: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Date: Tue, 15 Dec 2015 19:25:16 -0500
Subject: [PATCH] gl: Allow using non-system mesa with both GL and GLES

GCC automatically disable redundance warnings for system headers. As
soon as we start using a non-system installed mesa, we would start
having issues. The test for both wasn't setting any flags, so it would
work but then fail at runtime.

This is being fixed by disabling in the code (where needed only) that
GCC warning. The test is also fixed to avoid the false positive we had.
---
 configure.ac               | 13 +++++++++----
 gst-libs/gst/gl/gstglapi.h | 11 +++++++++++
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/configure.ac b/configure.ac
index f2d3c24839..0119ec2246 100644
--- a/configure.ac
+++ b/configure.ac
@@ -816,6 +816,10 @@ fi
 dnl check if we can include both GL and GLES2 at the same time
 if test "x$HAVE_GL" = "xyes" -a "x$HAVE_GLES2" = "xyes"; then
   GL_INCLUDES="
+#ifdef __GNUC__
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored \"-Wredundant-decls\"
+#endif
 #ifndef GL_GLEXT_PROTOTYPES
 #define GL_GLEXT_PROTOTYPES 1
 #endif
@@ -839,11 +843,12 @@ if test "x$HAVE_GL" = "xyes" -a "x$HAVE_GLES2" = "xyes"; then
 #   include <GL/glext.h>
 #  endif
 # endif
+int main (int argc, char **argv) { return 0; }
 "
   AC_MSG_CHECKING([whether it is possible to include both GL and GLES2 headers])
-  save_CPPFLAGS="$CPPFLAGS"
-  CPPFLAGS="$CPPFLAGS $ERROR_CFLAGS"
-  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[$GL_INCLUDES]], [[
+  save_CFLAGS="$CFLAGS"
+  CFLAGS="$CFLAGS $GL_CFLAGS $GLES2_CFLAGS $WARNING_CFLAGS $ERROR_CFLAGS"
+  AC_COMPILE_IFELSE([AC_LANG_SOURCE([[$GL_INCLUDES]], [[
     #if !defined(GL_FALSE)
     #error Failed to include GL headers
     #endif
@@ -861,7 +866,7 @@ if test "x$HAVE_GL" = "xyes" -a "x$HAVE_GLES2" = "xyes"; then
       HAVE_GLES2=no
     fi
   ])
-  CPPFLAGS="$save_CPPFLAGS"
+  CFLAGS="$save_CFLAGS"
 fi
 
 #dnl Check for OpenGL
diff --git a/gst-libs/gst/gl/gstglapi.h b/gst-libs/gst/gl/gstglapi.h
index dd44b45239..ab1a203f52 100644
--- a/gst-libs/gst/gl/gstglapi.h
+++ b/gst-libs/gst/gl/gstglapi.h
@@ -23,6 +23,13 @@
 
 #include <gst/gl/gstglconfig.h>
 
+/* This mimic GCC behaviour with system headers files even if GL headers may
+ * not be in the system header path. */
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wredundant-decls"
+#endif
+
 /* OpenGL 2.0 for Embedded Systems */
 #if GST_GL_HAVE_GLES2
 #ifndef GL_GLEXT_PROTOTYPES
@@ -57,6 +64,10 @@
 # endif
 #endif
 
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
+
 #ifdef WINAPI
 #define GSTGLAPI WINAPI
 #else