[cairo] [PATCH] cairo-gl: Fix build with -Werror -Wundef

[Olivier Blin]

Testing undefined macros is an error with -Werror -Wundef.
This is important to fix in cairo-gl.h since this is a public header.

This reverts commit c7cf0dfd602355e0c4fd1126e63844c304c1ef45 (which
was already a revert), and thus introduces back commits
c8b6c6066a238cf4cb04679e1149e956b1556a0c and
06a2696d5fa0ea50adb1463e2ee923ac92aabbdf.

This also adds new checks for CAIRO_HAS_GL_SURFACE and
CAIRO_HAS_GLESV2_SURFACE.
---
 src/cairo-gl.h | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/cairo-gl.h b/src/cairo-gl.h
index 9fd7608..7982b63 100644
--- a/src/cairo-gl.h
+++ b/src/cairo-gl.h
@@ -62,7 +62,8 @@
 
 #include "cairo.h"
 
-#if CAIRO_HAS_GL_SURFACE || CAIRO_HAS_GLESV2_SURFACE
+#if defined(CAIRO_HAS_GL_SURFACE) && CAIRO_HAS_GL_SURFACE || \
+    defined(CAIRO_HAS_GLESV2_SURFACE) && CAIRO_HAS_GLESV2_SURFACE
 
 CAIRO_BEGIN_DECLS
 
@@ -92,7 +93,7 @@ cairo_public void
 cairo_gl_device_set_thread_aware (cairo_device_t	*device,
 				  cairo_bool_t		 thread_aware);
 
-#if CAIRO_HAS_GLX_FUNCTIONS
+#if defined(CAIRO_HAS_GLX_FUNCTIONS) && CAIRO_HAS_GLX_FUNCTIONS
 #include <GL/glx.h>
 
 cairo_public cairo_device_t *
@@ -110,7 +111,7 @@ cairo_gl_surface_create_for_window (cairo_device_t *device,
 				    int width, int height);
 #endif
 
-#if CAIRO_HAS_WGL_FUNCTIONS
+#if defined(CAIRO_HAS_WGL_FUNCTIONS) && CAIRO_HAS_WGL_FUNCTIONS
 #include <windows.h>
 
 cairo_public cairo_device_t *
@@ -126,7 +127,7 @@ cairo_gl_surface_create_for_dc (cairo_device_t		*device,
 				int			 height);
 #endif
 
-#if CAIRO_HAS_EGL_FUNCTIONS
+#if defined(CAIRO_HAS_EGL_FUNCTIONS) && CAIRO_HAS_EGL_FUNCTIONS
 #include <EGL/egl.h>
 
 cairo_public cairo_device_t *
-- 
2.6.2