Implement new revision of extension GL_AMD_shader_ballot

- Add support for invocation functions with "InclusiveScan" and
  "ExclusiveScan" modes.
- Add support for invocation functions taking int64/uint64/doube/float16
  as inout data types.

SPIRV/SpvBuilder.h

@@ -555,7 +555,7 @@ public:
 
     SourceLanguage source;
     int sourceVersion;
-    std::set<const char*> extensions;
+    std::set<std::string> extensions;
     std::vector<const char*> sourceExtensions;
     AddressingModel addressModel;
     MemoryModel memoryModel;