tree 4599b513e07c511eb5641fd6ce533dd48523625a
parent 863f7eb6d7237b47a4347a2c517fd435a0edd44f
author Brad King <brad.king@kitware.com> 1565012580 -0400
committer Brad King <brad.king@kitware.com> 1565012580 -0400

clang: Work around toolchain file use of internal CMake variables

Since commit d44c0db0b2 (clang: setup correct configuration in gnu mode,
2019-02-20, v3.15.0-rc1~41^2~5) our Clang compiler information modules
need the `CMAKE_<LANG>_COMPILER_FRONTEND_VARIANT` variable that we
compute during compiler detection.  However, some existing toolchain
files set our internal `CMAKE_<LANG>_COMPILER_ID_RUN` variables and
block that detection, but do not set the new frontend variant variable.
Help them out by setting `CMAKE_<LANG>_COMPILER_FRONTEND_VARIANT` anyway.

Fixes: #19515, #19539