want -fforce-omit-frame-pointer option

[pfmooney]

Although the unwillingness for the patched-for-illumos gcc to omit frame pointers is useful nearly all of the time, there are occasions when it is unacceptable. There is a small body of software (such as BIOSes and JITs) where forcefully including frame pointers can negatively impact the correctness of the compiled artifacts. We should include an escape hatch -fforce-omit-frame-pointer for use in such situations.

[citrus-it]

Although I'd completely forgotten that I did it, the OmniOS gcc-12 has this option.

omniosorg@5fe0e17