CXXFLAGS overrides default flags, CFLAGS doesn't

[mglisse]

distutils/distutils/sysconfig.py

Lines 343 to 345 in 378984e

	cflags = _add_flags(cflags, 'C')
	ldshared = _add_flags(ldshared, 'C')
	cxxflags = os.environ.get('CXXFLAGS', cxxflags)

distutils now uses CXXFLAGS instead of CFLAGS for C++, that's good. However, it was implemented differently: while CFLAGS is appended to the default flags, CXXFLAGS replaces them. Is there a particular reason for this inconsistency? I have an application where I was setting both CFLAGS and CXXFLAGS to the same value, and was quite confused when the behavior changed with the new setuptools.