I want to replace custom byte-compiling function with calls to
compileall before 3.3b1, but in the short term it’s good to have this
fixed.
Adapted from the distutils patch by Jeff Ramnani. I tested with -B, -O
and -OO; test_util and test_mixin2to3 fail in -O mode because lib2to3
doesn’t support it.
PEP 370 features and sys.dont_write_bytecode are always available
in 3.3; the distutils2 backport still has the conditionals.
I also renamed an internal misnamed method and fixed a few things
(“packaging2” name, stray print, unused import, fd leak).
