Making ports work with clang, report #2

[Andrius Morkūnas]

I'm [still] working on creating an easy way to change ports compiler without
breaking too much stuff. http://wiki.freebsd.org/SOC2010AndriusMorkunas

Last week I've written a patch for bsd.port.mk that allows to set ports
compiler by defining PORTS_CC in make.conf. I intend to handle newer gcc
versions properly, but right now anything other than "gcc" or "clang"
will probably break something or will not work as intended.
I've also implemented USE_CC, which should replace USE_GCC at least for
some ports.

This week will probably be spent by trying to get support for other gcc
versions, handling the situation when clang is not installed, and some
other edge cases that will cause problems when users try to do something
crazy with PORTS_CC and/or PORTS_CXX.

-- 
Andrius