Check if RASTERIZER_DISCARD state is available

renderdoc/driver/gl/gl_common.h

@@ -398,6 +398,7 @@ extern bool IsGLES;
 // 99 means the extension never became core, so you can easily just do a check of CoreVersion >= NN
 // and they will always fail.
 #define EXTENSION_CHECKS()                                       \
+  EXT_TO_CHECK(30, 30, EXT_transform_feedback)                   \
   EXT_TO_CHECK(30, 30, EXT_draw_buffers2)                        \
   EXT_TO_CHECK(31, 99, ARB_texture_buffer_object)                \
   EXT_TO_CHECK(33, 30, ARB_explicit_attrib_location)             \

renderdoc/driver/gl/gl_renderstate.cpp

@@ -703,6 +703,7 @@ bool GLRenderState::CheckEnableDisableParam(GLenum pname)
   {
     case eGL_BLEND_ADVANCED_COHERENT_KHR: return HasExt[KHR_blend_equation_advanced_coherent];
     case eGL_RASTER_MULTISAMPLE_EXT: return HasExt[EXT_raster_multisample];
+    case eGL_RASTERIZER_DISCARD: return HasExt[EXT_transform_feedback];
     default: break;
   }