This usually happens when the build dir is a subdir of the source dir. It is now detected during runtime, using the length of the relative path from the build dir to the source dir as the length of the prefix to skip, if __FILE__ starts with a '.'.
Also fix the escaping of REACTOS_*_DIR defines. It was gracefully fixed up by CMake, but resulted in broken syntax highliting.
CORE-14839 #resolve
* Remove unused cmake modules - Both are unedited versions of modules provided by cmake itself
* Remove Compiler/GNU.cmake - Only chang was various _INIT flags, which are handled
via CMAKE_USER_MAKE_RULES_OVERRIDE instead
* Remove Platform/Windows.cmake - There's no clear explination for this file being in reactos
and is simply an old version of the one in cmake
* Remove Platform/Windows-MSVC.cmake - _INIT variable changes moved to overrides-msvc.cmake
Remove /implib from link commands
* Remove CMakeDetermineASMCompiler.cmake - Only change from 3.2 is the addition of a compiler list for the generic ASM dialect, but toolchain files explicitly set a compiler so the list is never used