add Makefile.inc to "make" type

[bad]

The *BSD build systems make use of "Makefile.inc" a lot. Make the "make" type recognize this file by default.

[okdana]

You might consider generalising this to Makefile.* actually. It's common to use this naming convention for alternate Makefiles, e.g. for different targets. An extreme example of this is RetroArch, but even FreeBSD has some other instances that the change in its current form wouldn't address

(If you did do it that way, i would suggest Makefile.* instead of [Mm]akefile.* because the latter seems too prone to false positives in this case)

[bad]

Is there a reason this PR hasn't been merged yet?

[BurntSushi]

Sometimes it just takes me a while.

Otherwise I think I agree with @okdana's feedback here.

[bad]

Thanks for the quick response.

I'm fine with @okdana's suggestion and changed the code.