Semantic Issue Use of undeclared identifier 'GL_BGRA_EXT'

Help!!

im such a newbie to getting Unity to talk with Xcode. Ive signed up for a developers program and done all the necessary steps (i think) in this tutorial http://docs.unity3d.com/Manual/iphone-accountsetup.html however unity doesn't seem to pass on the build to xcode properly, i always have to reopen the project manually in xcode and secondly im getting the following error in xcode:

Semantic Issue Use of undeclared identifier 'GL_BGRA_EXT'

 #include "CMVideoSampling.h"
  
  
  
 #include "CVTextureCache.h"
  
 #include "GLESHelper.h"
  
  
  
 #include <OpenGLES/ES2/gl.h>
  
 #include <AVFoundation/AVFoundation.h>
  
  
  
 void CMVideoSampling_Initialize(CMVideoSampling* sampling)
  
 {
  
     ::memset(sampling, 0x00, sizeof(CMVideoSampling));
  
     if(CanUseCVTextureCache())
  
         sampling->cvTextureCache = CreateCVTextureCache();
  
     else
  
         GLES_CHK(glGenTextures(2, (GLuint*)sampling->glTex));
  
 }
  
  
  
 void CMVideoSampling_Uninitialize(CMVideoSampling* sampling)
  
 {
  
     if(sampling->cvTextureCacheTexture)
  
     {
  
         CFRelease(sampling->cvTextureCacheTexture);
  
         sampling->cvTextureCacheTexture = 0;
  
     }
  
     if(sampling->cvTextureCache)
  
     {
  
         CFRelease(sampling->cvTextureCache);
  
         sampling->cvTextureCache = 0;
  
     }
  
     if(sampling->glTex[0])
  
     {
  
         GLES_CHK(glDeleteTextures(2, (GLuint*)sampling->glTex));
  
         sampling->glTex[0] = sampling->glTex[1] = 0;
  
     }
  
 }
  
  
  
 int CMVideoSampling_SampleBuffer(CMVideoSampling* sampling, void* buffer, int w, int h)
  
 {
  
     int retTex = 0;
  
  
  
     CVImageBufferRef cvImageBuffer = CMSampleBufferGetImageBuffer((CMSampleBufferRef)buffer);
  
     if(CanUseCVTextureCache())
  
     {
  
         if(sampling->cvTextureCacheTexture)
  
         {
  
             CFRelease(sampling->cvTextureCacheTexture);
  
             FlushCVTextureCache(sampling->cvTextureCache);
  
         }
  
         sampling->cvTextureCacheTexture = CreateTextureFromCVTextureCache(sampling->cvTextureCache, cvImageBuffer, w, h, GL_BGRA_EXT, GL_RGBA, GL_UNSIGNED_BYTE);
  
         if(sampling->cvTextureCacheTexture)
  
             retTex = GetGLTextureFromCVTextureCache(sampling->cvTextureCacheTexture);
  
     }
  
     else
  
     {
  
         retTex = sampling->glTex[1];
  
  
  
         CVPixelBufferLockBaseAddress(cvImageBuffer,0);
  
         void* texData = CVPixelBufferGetBaseAddress(cvImageBuffer);
  
  
  
         // TODO: provide unity interface?
  
         GLES_CHK(glBindTexture(GL_TEXTURE_2D, retTex));
  
         GLES_CHK(glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_BGRA_EXT, GL_UNSIGNED_BYTE, texData));
  
  
  
         CVPixelBufferUnlockBaseAddress(cvImageBuffer,0);
  
  
  
         // swap read and draw textures
  
         {
  
             int __temp = sampling->glTex[0];
  
             sampling->glTex[0] = sampling->glTex[1];
  
             sampling->glTex[1] = __temp;
  
         }
  
     }
  
  
  
     GLES_CHK(glBindTexture(GL_TEXTURE_2D, retTex));
  
     GLES_CHK(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR));
  
     GLES_CHK(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR));
  
     GLES_CHK(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE));
  
     GLES_CHK(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE));
  
     GLES_CHK(glBindTexture(GL_TEXTURE_2D, 0));
  
  
  
     return retTex;
  
 }
  
  
  
 int  CMVideoSampling_LastSampledTexture(CMVideoSampling* sampling)
  
 {
  
     return sampling->cvTextureCacheTexture ? GetGLTextureFromCVTextureCache(sampling->cvTextureCacheTexture) : sampling->glTex[0];
  
 }
  

Any ideas? ive started from scratch with a basic scene with just a cube in it to eliminate any other issues. please help

cheers