customized make flags

[autosquid]

the flag used current is only -C to appoint build dir. However flags such as -k may be useful too. Is there a way to use customized make flags? I hope this feature added to make this package more flexible.

[redguardtoo]

Technically it's not difficult, What about a global flag like cppcm-compile-extra-flag? I will see what I can do.