When compiling Python 3.3.1, I noticed that some variables like LDFLAGS or CFLAGS in sysconfig have some flags multiple times. (Which BTW breaks distutils.tests.{test_sysconfig_compiler_vars,test_sysconfig_module}) This is caused by interpretation of Makefile in sysconfig._parse_makefile(), which seems to evaluate the variables in Makefile - but some variables in Makefile are formed by expanding env variables multiple times, e.g.:
PY_LDFLAGS=        $(CONFIGURE_LDFLAGS) $(LDFLAGS)
CONFIGURE_LDFLAGS=        @LDFLAGS@
so when doing the build from scratch with configure & make, PY_LDFLAGS gets the content of LDFLAGS twice  (as far as I remember autotools...), CFLAGS gets expanded like 5 times at least.
I think that this is not the correct behaviour, but not sure, maybe I'm doing something wrong.

Thanks.