`cmake_check_c_compiler_flag` does not appear to work for the TI `armcl` compiler. I believe this is because a pattern akin to `"invalid compiler option.*\(ignored\)"` is not listed in [CHECK_COMPILER_FLAG_COMMON_PATTERNS](https://gitlab.kitware.com/cmake/cmake/-/blob/master/Modules/CMakeCheckCompilerFlagCommonPatterns.cmake). Here is an example of the TI compiler's invalid flag output: ``` /opt/ti/ti-cgt-arm_18.12.2.LTS/bin/armcl c.c -Wall --emit_warnings_as_errors >> WARNING: invalid compiler option --Wall (ignored) ``` Unfortunately, `--emit_warnings_as_errors` does not force a non-zero exit code in this case, nor does `--diag_error=#`, where `#` is `[1-9999]` (I was hoping some diagnostic number would be tied to this).