GLSL fixes:

GLSL fixes:
- generate error on NULL pointers in glShaderSourceARB;
- reinstall program object, if current, in glLinkProgramARB;
- vertex and fragment shaders are optional in program object;
- floor asm was wrongly computed for x86 back-end;
- allow for (void) idiom in function prototypes;
- all fixed-state uniforms are updated;
- local variable initializers are working;
- implement texture* and shadow* functions for vertex processor;
- generate error if too many arguments in general constructor;
- trim unused data in general constructor;
- struct r-value field select was badly relocated;

Changes:
- add derived state gl_fog_attrib::_Scale;
- add derived state gl_light::_CosCutoffNeg;