Fixes for Clang 10 compatibility (closes #965) (#968)

Primarily FrontendAction now gets passed as unique_ptr, but also StringRef was added in a few places. See https://releases.llvm.org/10.0.0/tools/clang/docs/ReleaseNotes.html#internal-api-changes and http://llvm.org/docs/ProgrammersManual.html#the-stringref-class Also, llvm::make_unique is now std::make_unique: https://reviews.llvm.org/D66259 because LLVM requires C++14.

src/lib_cxx/data/parser/cxx/utilityClang.cpp

@@ -3,6 +3,7 @@
 #include <clang/AST/DeclCXX.h>
 #include <clang/AST/DeclTemplate.h>
 #include <clang/Lex/Preprocessor.h>
+#include <clang/Basic/FileManager.h>
 
 #include "CanonicalFilePathCache.h"
 #include "FilePath.h"
@@ -130,10 +131,10 @@ std::wstring utility::getFileNameOfFileEntry(const clang::FileEntry* entry)
 	std::wstring fileName = L"";
 	if (entry != nullptr && entry->isValid())
 	{
-		fileName = utility::decodeFromUtf8(entry->tryGetRealPathName());
+		fileName = utility::decodeFromUtf8(entry->tryGetRealPathName().str());
 		if (fileName.empty())
 		{
-			fileName = utility::decodeFromUtf8(entry->getName());
+			fileName = utility::decodeFromUtf8(entry->getName().str());
 		}
 		else
 		{