LLVM build failure on Windows with Visual Studio 2015

[juj]

Building on Windows Visual Studio 2015 after the latest LLVM merge, there are three different issues, of which two are LLVM lit test suite specific, and the third one in Clang even when tests are disabled. Tracking these in the LLVM bug tracker:

• https://llvm.org/bugs/show_bug.cgi?id=26087: Building clangDynamicASTMatchers fails on Visual Studio 2015 in REGISTER_MATCHER(hasDeclaration);
• https://llvm.org/bugs/show_bug.cgi?id=26088: Some AST matcher tests fail to compile on Visual Studio 2015.
• https://llvm.org/bugs/show_bug.cgi?id=26089: Clang unit test build failure with fatal error C1128: number of sections exceeded

[juj]

Fixed by above PR.