title: GLSL compilation error when using QGLShaderProgram
body: <p>I'm currently trying out some of the opengl components in Qt 5, I'm compiling on Mac OSX 10.8 with QtCreator 2.6.2, clang 4.2
  I've written a very basic GLSL shader that compiles and links well in OpenGl Shader Builder, but when I try to load it using a QGLShader, it fails to compile and the log function returns no error message.</p>
  
  <p>Vertex Shader:</p>
  
  <pre><code>attribute vec4 in_position;
  attribute vec3 in_normal;
  attribute vec3 in_color;
  attribute vec2 in_tex;
  
  uniform vec4 lightPosition;
  
  varying vec2 texCoords;
  varying vec3 normal;
  varying vec3 vertToLightDir;
  
  void main(void)
  {
      gl_Position = gl_ModelViewProjectionMatrix * in_position;
      vec4 worldVert = gl_ModelViewMatrix * in_position;
      vertToLightDir = normalize(vec3(lightPosition - worldVert));
      normal = gl_NormalMatrix * in_normal;
      texCoords = in_tex;
  }
  </code></pre>
  
  <p>Fragment Shader:</p>
  
  <pre><code>uniform sampler2D texture0;
  uniform vec4 lightColor;
  
  varying vec2 texCoords;
  varying vec3 normal;
  varying vec3 vertToLightDir;
  
  void main(void)
  {
      float lightIntensity = clamp(dot(normal, vertToLightDir), 0.0, 1.0);
      gl_FragColor = (texture2D(texture0, texCoords) + (lightColor * lightIntensity)) * 0.5;
  }
  </code></pre>
  
  <p>The code that loads the shaders:</p>
  
  <pre><code>QGLShader fragShader(QGLShader::Fragment);
  bool success = fragShader.compileSourceFile("Fragment.glsl");
  qDebug() &lt;&lt; fragShader.log();
  </code></pre>
  
  <p>I used the debugger to see that the compileSourceFile function returns false, I also used access("Fragment.glsl", F_OK) to see if the program manages to find the file and it does, the same goes for the vertex shader file, I can't seem to find the reason they won't compile. Is there something I'm doing wrong ?</p>