Fixed some version information in flang/f18:
- fixed the behavior of the -v switch: this flag enables verbosity with used with arguments, but just displays the version when used alone (related to this bug: https://bugs.llvm.org/show_bug.cgi?id=46017)
- added FLANG, FLANG_MAJOR, FLANG_MINOR__ and FLANG_PATCHLEVEL (similar to their __F18* counterparts) for compatibility purpose
Can you use CMAKE_CURRENT_BINARY_DIR to configure the file? Source directory should be read only and not written to.