Add support for SPV_NV_sample_mask_override_coverage

CMakeLists.txt

@@ -3,6 +3,8 @@ set_property(GLOBAL PROPERTY USE_FOLDERS ON)
 
 option(ENABLE_AMD_EXTENSIONS "Enables support of AMD-specific extensions" ON)
 
+option(ENABLE_NV_EXTENSIONS "Enables support of Nvidia-specific extensions" ON)
+
 enable_testing()
 
 set(CMAKE_INSTALL_PREFIX "install" CACHE STRING "prefix")
@@ -13,6 +15,10 @@ if(ENABLE_AMD_EXTENSIONS)
     add_definitions(-DAMD_EXTENSIONS)
 endif(ENABLE_AMD_EXTENSIONS)
 
+if(ENABLE_NV_EXTENSIONS)
+    add_definitions(-DNV_EXTENSIONS)
+endif(ENABLE_NV_EXTENSIONS)
+
 if(WIN32)
     set(CMAKE_DEBUG_POSTFIX "d")
     include(ChooseMSVCCRT.cmake)