libgltf: check for #version string in the shader before add an own one.

Change-Id: I69dbbabc5774cbce7943e77f41bb42ed7a118bcf

external/libgltf/patches/append_shader_version.patch

 diff -ur libgltf.org/src/Shaders.cpp libgltf/src/Shaders.cpp
---- libgltf.org/src/Shaders.cpp	2014-08-17 09:15:17.379255115 +0200
-+++ libgltf/src/Shaders.cpp	2014-08-17 09:16:43.323258781 +0200
+--- libgltf.org/src/Shaders.cpp	2014-08-18 09:19:48.323955939 +0200
++++ libgltf/src/Shaders.cpp	2014-08-18 09:20:46.711953465 +0200
 @@ -11,6 +11,7 @@
  
  #include <GL/glew.h>
@@ -9,11 +9,13 @@ diff -ur libgltf.org/src/Shaders.cpp libgltf/src/Shaders.cpp
  
  namespace libgltf
  {
-@@ -166,7 +167,17 @@
+@@ -166,7 +167,24 @@
                                    unsigned int shaderId)
  {
      GLint iGLSize = iSize;
 -    glShaderSource(shaderId, 1, &pShader, &iGLSize);
++    if( strstr(pShader,"#version") == 0 )
++    {
 +        const GLchar* aSources[] = {
 +            "#version 130\n",
 +            pShader,
@@ -25,6 +27,11 @@ diff -ur libgltf.org/src/Shaders.cpp libgltf/src/Shaders.cpp
 +        };
 +
 +        glShaderSource(shaderId, 2, &aSources[0], &aSizes[0]);
++    }
++    else
++    {
++        glShaderSource(shaderId, 1, &pShader, &iGLSize);
++    }
      glCompileShader(shaderId);
      int iStatus = 0;
      glGetShaderiv(shaderId, GL_COMPILE_STATUS, &iStatus);