Issue #15188: Prevent test_ldshared_value failure due to slightly

Issue #15188: Prevent test_ldshared_value failure due to slightly
different parsing of the Makefile by distutils.sysconfig and
sysconfig in the case when an intermediate config vars, used to
construct PY_CFLAGS or PY_LDFLAGS, has a trailing space character.
In this case, the OS X installer build script was leaving a
trailing space in the OPT and LDFLAGS config vars.  The space is not
significant and it's not worth toying with the Makefile parsing.