https://github.com/RobertBeckebans/RBDOOM-3-BFG

* radeonsi driver (Pitcairn XT)
* mesa-git trunk
* llvm-svn

RBDoom3-BFG fail to build shaders with the following error:
---------->8----------
----- Initializing Render Shaders -----
While compiling vertex program renderprogs/gui.vertex
-----------------
  1: #version 150
  2: #define PC
  3: 
  4: float saturate( float v ) { return clamp( v, 0.0, 1.0 ); }
  5: vec2 saturate( vec2 v ) { return clamp( v, 0.0, 1.0 ); }
  6: vec3 saturate( vec3 v ) { return clamp( v, 0.0, 1.0 ); }
  7: vec4 saturate( vec4 v ) { return clamp( v, 0.0, 1.0 ); }
  8: vec4 tex2Dlod( sampler2D sampler, vec4 texcoord ) { return textureLod( sampler, texcoord.xy, texcoord.w ); }
  9: 
 10: 
 11: uniform vec4 _va_[4];
 12: 
 13: float dot4 (vec4 a , vec4 b ) {return dot ( a , b ) ; }
 14: float dot4 (vec2 a , vec4 b ) {return dot ( vec4 ( a , 0 , 1 ) , b ) ; }
 15: vec4 swizzleColor (vec4 c ) {return c ; }
 16: 
 17: in vec4 in_Position;
 18: in vec2 in_TexCoord;
 19: in vec4 in_Normal;
 20: in vec4 in_Tangent;
 21: in vec4 in_Color;
 22: in vec4 in_Color2;
 23: 
 24: out vec4 gl_Position;
 25: out vec2 vofi_TexCoord0;
 26: out vec4 vofi_TexCoord1;
 27: out vec4 gl_FrontColor;
 28: 
 29: void main() {
 30:    gl_Position . x = dot4 ( in_Position , _va_[0 /* rpMVPmatrixX */] ) ;
 31:    gl_Position . y = dot4 ( in_Position , _va_[1 /* rpMVPmatrixY */] ) ;
 32:    gl_Position . z = dot4 ( in_Position , _va_[2 /* rpMVPmatrixZ */] ) ;
 33:    gl_Position . w = dot4 ( in_Position , _va_[3 /* rpMVPmatrixW */] ) ;
 34:    vofi_TexCoord0 . xy = in_TexCoord . xy ;
 35:    vofi_TexCoord1 = ( swizzleColor ( in_Color2 ) * 2 ) - 1 ;
 36:    gl_FrontColor = swizzleColor ( in_Color ) ;
 37: }
-----------------
0:24(10): error: `gl_Position' redeclared
0:27(1): error: identifier `gl_FrontColor' uses reserved `gl_' prefix
----------8<----------

Changing _mesa_glsl_error() into _mesa_glsl_warning() makes the game start, but content of the window is now garbled/black.

An apitrace of RBDoom3-BFG is available here:
http://pkgbuild.com/~lcarlier/traces/RBDoom3BFG.trace.tar.xz

Upstream bugreports are available here:
https://github.com/RobertBeckebans/RBDOOM-3-BFG/issues/86
https://github.com/RobertBeckebans/RBDOOM-3-BFG/issues/52