glsl: add several EmitNo* options, and MaxUnrollIterations

This increases the chance that GLSL programs will actually work.

Note that continues and returns are not yet lowered, so linking
will just fail if not supported.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>

src/glsl/ir_optimization.h

@@ -28,7 +28,7 @@
  * Prototypes for optimization passes to be called by the compiler and drivers.
  */
 
-bool do_common_optimization(exec_list *ir, bool linked);
+bool do_common_optimization(exec_list *ir, bool linked, unsigned max_unroll_iterations);
 
 bool do_algebraic(exec_list *instructions);
 bool do_constant_folding(exec_list *instructions);