we temporarily store all buildsystem-set conditionals into
OUR_CPPFLAGS and write it into config.mak as an addition to eventually
user-supplied CPPFLAGS. this should prevent crucial things we set from
being overwritten by a user that has CPPFLAGS exported.
fixes#142
apparently mktemp on OSX 10.9.5 requires a parameter.
instead of playing whack-a-mole with apple we now use the portable
code from musl's configure script which should work everywhere.
adresses #142
this should fix the build of the recently added ipv6 code on MacOS X,
OpenBSD and eventually FreeBSD.
closes#83closes#85
thanks to @cam13 and @vonnyfly for reporting/testing.