This port had two main problems:
1) failure to set the enviroment in the build target
2) failure to use CXXFLAGS with CXX
While fixing those, clean up a bit:
3) remove <pre>,<post> by using BROKEN_powerpc instead
4) use CFLAGS+= to augment CFLAGS
5) use LDFLAGS+= to augment LDFLAGS
6) simplify do-build target accordingly
Approved by: just fix it
All versions of FreeBSD we support are shipped with at least GCC 4.2.1
or Clang. The code seems to build fine with Clang. In fact, on platforms
where we no longer ship libstdc++, this port seems to only build using
Clang.
