Compiling pkgsrc Packages with an Alternative libc

[Thomas Cort <tcort%minix3.org@localhost>]

Hello,

I'm working on pkgsrc for the Minix project. We're in the process of
replacing our C library with a modified version of NetBSD's libc. All
of the stuff ported from NetBSD (libc, headers, ...) is in
/usr/netbsd/{lib,include,...}. There are also a couple of helper
libraries in /usr/netbsd/lib (compat_minix and minlib). We want to be
able to compile pkgsrc packages using that libc, but pkgsrc seems to
be re-writing the compilation commands. Using the same CFLAGS/LDFLAGS
we can compile the sources outside of pkgsrc.

What's the cleanest way to implement compiling against another libc
(is there something that already does this? maybe something cross
compiler related?), and what do we need to do to link against the 2
base system libraries in /usr/netbsd/lib?

Thanks,
-Thomas