Patch from github.

At the moment it is not possible to build ROCr with Clang. This is
a spurious limitation. The present PR addresses it by guarding GCC
only flags and by fixing some additional warnings that Clang triggers;
one of said warnings did outline a rather interesting issue with math
being done on void*s. - AlexVlx

Void ptr arithmetic had already been fixed in amd-master branch.

Change-Id: I5ee97e20b5c40b10dd73facecabe75f02ba46462

runtime/hsa-runtime/loader/executable.hpp

@@ -115,9 +115,9 @@ protected:
     , is_definition(_is_definition)
     , address(_address) {}
 
-  virtual bool GetInfo(hsa_symbol_info32_t symbol_info, void *value);
+  virtual bool GetInfo(hsa_symbol_info32_t symbol_info, void* value) override;
 
-private:
+ private:
   SymbolImpl(const SymbolImpl &s);
   SymbolImpl& operator=(const SymbolImpl &s);
 };