[clang] [flang] [flang][driver] Introduce FCC_OVERRIDE_OPTIONS. (PR #140556)

[Kiran Chandramohan via cfe-commits]

kiranchandramohan wrote:

Does `CCC_OVERRIDE_OPTIONS` expands to Clang Compiler Commandline Override Options? If so `FCC_OVERRIDE_OPTIONS` expanding to Fortran Compiler Commandline Override Options seems the right replacement.

If `CCC_OVERRIDE_OPTIONS` expands to Clang C Compiler Override Options then `FFC_OVERRIDE_OPTIONS` (as suggested by @tarunprabhu) expanding to Flang Fortran Compiler Overrided Options is better.

https://github.com/llvm/llvm-project/pull/140556