Add support for new glShaderSource() signature from Khronos.  Disabled by default.

Review URL: https://codereview.appspot.com/6853068

git-svn-id: http://skia.googlecode.com/svn/trunk@6491 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/gpu/GrConfig.h b/include/gpu/GrConfig.h
index cd081ef..766212d 100644
--- a/include/gpu/GrConfig.h
+++ b/include/gpu/GrConfig.h
@@ -375,6 +375,15 @@
     #define GR_DEFAULT_TEXTURE_CACHE_MB_LIMIT 96
 #endif
 
+/**
+ * GR_USE_NEW_GL_SHADER_SOURCE_SIGNATURE is for compatibility with the new version
+ * of the OpenGLES2.0 headers from Khronos.  glShaderSource now takes a const char * const *,
+ * instead of a const char **.
+ */
+#if !defined(GR_USE_NEW_GL_SHADER_SOURCE_SIGNATURE)
+    #define GR_USE_NEW_GL_SHADER_SOURCE_SIGNATURE 0
+#endif
+
 ///////////////////////////////////////////////////////////////////////////////
 // tail section:
 //