[Python-Dev] distutils doesn't use some compiler options when building

[Akira Kitada]

Hi,

I encountered a weird problem using distutils.
Generally, distutils try to use the same compiler options used for
building Python interpreter,
but it looks like some of them are omitted sometimes.

- CPPFLAGS are not retrieved from the config and only ones in env are used.
- OPT is retrieved from the config, but it's only used when env has CFLAGS.

See: http://svn.python.org/view/python/trunk/Lib/distutils/sysconfig.py

"""
def customize_compiler(compiler):
...
    if compiler.compiler_type == "unix":
        (cc, cxx, opt, cflags, ccshared, ldshared, so_ext) = \
            get_config_vars('CC', 'CXX', 'OPT', 'CFLAGS',
                            'CCSHARED', 'LDSHARED', 'SO')

        if 'CC' in os.environ:
            cc = os.environ['CC']
        if 'CXX' in os.environ:
            cxx = os.environ['CXX']
        if 'LDSHARED' in os.environ:
            ldshared = os.environ['LDSHARED']
        if 'CPP' in os.environ:
            cpp = os.environ['CPP']
        else:
            cpp = cc + " -E"           # not always
        if 'LDFLAGS' in os.environ:
            ldshared = ldshared + ' ' + os.environ['LDFLAGS']
        if 'CFLAGS' in os.environ:
            cflags = opt + ' ' + os.environ['CFLAGS']
            ldshared = ldshared + ' ' + os.environ['CFLAGS']
        if 'CPPFLAGS' in os.environ:
            cpp = cpp + ' ' + os.environ['CPPFLAGS']
            cflags = cflags + ' ' + os.environ['CPPFLAGS']
            ldshared = ldshared + ' ' + os.environ['CPPFLAGS']

        cc_cmd = cc + ' ' + cflags
        compiler.set_executables(
            preprocessor=cpp,
            compiler=cc_cmd,
            compiler_so=cc_cmd + ' ' + ccshared,
            compiler_cxx=cxx,
            linker_so=ldshared,
            linker_exe=cc)

        compiler.shared_lib_extension = so_ext
"""

Are these logics are intentional or just a bug?
If this is intentional behavior, why is that being this way?

Thanks,