move CFLAGS and DEFS definitions (#467)
move CFLAGS and DEFS definitions (#467)

First, create some generic CFLAGS, with some warnings and optimizations.
Do the same for some macros.

Then the platform-specific configurations run, appending to CFLAGS, ZWOSDK,
and DEFS as appropriate.

Finally, combine these into the actual CFLAGS that will be passed to the
compiler. Found while wondering why "-O2" wasn't working for me.
thomasjacquin/allsky,thomasjacquin/allsky,thomasjacquin/allsky