Automatic scratch config's c_flags does not include extra_cflags

[LagoLunatic]

It includes all of the shared cflags but not the object-specific extra_cflags.

Example fix: https://github.com/zeldaret/tww/commit/7916599cad12c8a6809946ac07e8a2479f38a5cc

[encounter]

That fix looks good, I’d accept it as a PR if you were willing to open one. Otherwise I’ll copy it when I’m able.