Workaround crash with LLVM 7

If clazy is compiled with clang instead of gcc it might crash with:

10637== Process terminating with default action of signal 11 (SIGSEGV): dumping core

10637== Access not within mapped region at address 0x8

10637== at 0x19CDD8C: clang::ast_matchers::MatchFinder::MatchFinder(clang::ast_matchers::MatchFinder::MatchFinderOptions) (in /usr/lib/llvm-7/bin/clang)

10637== by 0x9D75670: ClazyASTConsumer (Clazy.cpp:62)

10637== by 0x9D75670: ClazyASTAction::CreateASTConsumer(clang::CompilerInstance&, llvm::StringRef) (Clazy.cpp:183)

10637== by 0x9E29ED: clang::FrontendAction::CreateWrappedASTConsumer(clang::CompilerInstance&, llvm::StringRef) (in /usr/lib/llvm-7/bin/clang)

10637== by 0x9E8FCA: clang::FrontendAction::BeginSourceFile(clang::CompilerInstance&, clang::FrontendInputFile const&) (in /usr/lib/llvm-7/bin/clang)

10637== by 0x9AE3D5: clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (in /usr/lib/llvm-7/bin/clang)

10637== by 0xA8C9FA: clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (in /usr/lib/llvm-7/bin/clang)

10637== by 0x5822C7: cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (in /usr/lib/llvm-7/bin/clang)

10637== by 0x571ACC: main (in /usr/lib/llvm-7/bin/clang)

After debugging clazy and clang's code I couldn't find anything wrong with it.
Valgrind's output doesn't make much sense, and simply compiling the Clazy.cpp
translation unit with gcc instead of clang makes the crash go away and valgrind's output is clean.

I'm assuming debian's LLVM was built with gcc and building clazy with clang
will have some sort of incompatibility, or maybe it's simply a clang bug.

The downside of this workaround is that qcolor-literal check will be disabled.
Next step will be producing a minimal test case and reporting to LLVM.

BUG: 392223
CCMAIL: Woebbeking@kde.org