Clang: Requires a clang debug build for windows

Under windows you cannot mix debug and release builds. So we require that
clang is build as debug if the creator is build in debug.

Change-Id: Ie46a1f13d83a7afbf81129ed75d0519fa9f5268d
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>

src/tools/clangrefactoringbackend/clangrefactoringbackend.pro

@@ -5,6 +5,11 @@ include(../../qtcreatortool.pri)
 include(../../shared/clang/clang_installation.pri)
 include(source/clangrefactoringbackend-source.pri)
 
+win32 {
+    LLVM_BUILDMODE = $$system($$llvm_config --build-mode, lines)
+    CONFIG(debug, debug|release):requires(equals(LLVM_BUILDMODE, "Debug"))
+}
+
 QT += core network
 QT -= gui