Fixed preprocessors errors on GCC

- Preprocessor variables need to be separated from string constants to be separated token
- Use ##__VA_ARGS__ GCC extension to support empry __VA_ARGS__ (should be no-op on MSVC). See:
http://www.delorie.com/gnu/docs/gcc/gcc_44.html
for details.

The following series fixes compilation on GCC (from mingw-w64) and allows cross compiling the source on Linux. It was tested in Mozilla tree since ANGLE has no support for GCC in its build system.

Issue=358
Signed-off-by: Daniel Koch

git-svn-id: https://angleproject.googlecode.com/svn/trunk@1259 736b8ea6-26fd-11df-bfd4-992fa37f6226
diff --git a/src/libGLESv2/libGLESv2.cpp b/src/libGLESv2/libGLESv2.cpp
index d48bf76..40a7067 100644
--- a/src/libGLESv2/libGLESv2.cpp
+++ b/src/libGLESv2/libGLESv2.cpp
@@ -3801,9 +3801,9 @@
           case GL_RENDERER:
             return (GLubyte*)((context != NULL) ? context->getRendererString() : "ANGLE");
           case GL_VERSION:
-            return (GLubyte*)"OpenGL ES 2.0 (ANGLE "VERSION_STRING")";
+            return (GLubyte*)"OpenGL ES 2.0 (ANGLE " VERSION_STRING ")";
           case GL_SHADING_LANGUAGE_VERSION:
-            return (GLubyte*)"OpenGL ES GLSL ES 1.00 (ANGLE "VERSION_STRING")";
+            return (GLubyte*)"OpenGL ES GLSL ES 1.00 (ANGLE " VERSION_STRING ")";
           case GL_EXTENSIONS:
             return (GLubyte*)((context != NULL) ? context->getExtensionString() : "");
           default: