devel/intel-graphics-compiler: unbreak on -CURRENT

-CURRENT now has Clang 10.0.1 and FreeBSD 12.2 may inherit it but
FreeBSD 11.4 is likely to keep Clang 10.0.0.

In file included from IGC/GenISAIntrinsics/GenIntrinsics.cpp:28:
In file included from IGC/Compiler/CodeGenPublic.h:44:
In file included from IGC/Compiler/CISACodeGen/helper.h:49:
In file included from IGC/Compiler/MetaDataApi/MetaDataApi.h:31:
In file included from IGC/Compiler/MetaDataApi/MetaDataApiUtils.h:30:
IGC/Compiler/MetaDataApi/MetaDataValue.h:82:20: error: cannot initialize return object of type 'llvm::MDNode *' with an lvalue of type 'llvm::Metadata *'

return m_pNode;
       ^~~~~~~

IGC/Compiler/MetaDataApi/MetaDataValue.h:260:23: error: assigning to 'llvm::Metadata *' from incompatible type 'llvm::Value *'

m_pNode = pNode;
          ^~~~~

IGC/Compiler/MetaDataApi/MetaDataValue.h:270:18: error: no viable overloaded '='

m_id = name;
~~~~ ^ ~~~~

IGC/Compiler/MetaDataApi/MetaDataValue.h:41:11: note: candidate function (the implicit copy assignment operator) not viable: no known conversion from 'const char *' to 'const IGC::MetaDataValue<std::__1::basic_string<char>, IGC::MDValueTraits<std::string, void> >' for 1st argument

class MetaDataValue
      ^

IGC/Compiler/MetaDataApi/MetaDataValue.h:41:11: note: candidate function (the implicit move assignment operator) not viable: no known conversion from 'const char *' to 'IGC::MetaDataValue<std::__1::basic_string<char>, IGC::MDValueTraits<std::string, void> >' for 1st argument

class MetaDataValue
      ^

IGC/Compiler/MetaDataApi/MetaDataValue.h:278:18: error: no viable overloaded '='

m_id = name.c_str();
~~~~ ^ ~~~~~~~~~~~~

IGC/Compiler/MetaDataApi/MetaDataValue.h:41:11: note: candidate function (the implicit copy assignment operator) not viable: no known conversion from 'const std::1::basic_string<char, std::1::char_traits<char>, std::1::allocator<char> >::value_type *' (aka 'const char *') to 'const IGC::MetaDataValue<std::1::basic_string<char>, IGC::MDValueTraits<std::string, void> >' for 1st argument

class MetaDataValue
      ^

IGC/Compiler/MetaDataApi/MetaDataValue.h:41:11: note: candidate function (the implicit move assignment operator) not viable: no known conversion from 'const std::1::basic_string<char, std::1::char_traits<char>, std::1::allocator<char> >::value_type *' (aka 'const char *') to 'IGC::MetaDataValue<std::1::basic_string<char>, IGC::MDValueTraits<std::string, void> >' for 1st argument

class MetaDataValue
      ^

Reported by: pkg-fallout