Detect whether cc (the linker) is gcc or clang.

Detect whether cc (the linker) is gcc or clang.

Use this information to drive which options are added to the `cc`
command line arguments.

As a drive-by, fix an english grammar mistake in a comment.

This is meant to be, in part, a more robust version of PR #17192.

Fix #17214.
It seems like getting the args_fmt is a bit of effort. Is it worth having a version of get_cc_prog which doesn't do it when its not needed?