Merge pull request #29 from asergi/master

Fix build on FreeBSD 9.x amd64
actually, revert treating musl-gcc as a native compiler, because it is not one!
support BUILDRUMP_LDFLAGS
cherry-pick fix for bogus(ish) compiler warning
Source for buildrump.sh git rev 4a6f5bcdc1c1baabcfbf3c34fc7e5834080e93ce
use egrep when necessary. part of issue #30
Don't put compat queue.h into DESTDIR so that it doesn't get installed.

Use a separate compat dir instead.  This still need a bit of finetuning,
though, since the compat dir should be consulted only for non-kernel
components.  However, the current CPPFLAGS granularity doesn't allow that,
and needs a bit of redesign-coming-your-way-soon.

Issue #28
do not use S from env, potential collisions. issue #30