Update after gnulib changed: Fix link errors on native Windows.
* autogen.sh (GNULIB_MODULES_TOOLS_FOR_SRC, GNULIB_MODULES_LIBGETTEXTPO): Add
strdup-posix.
Avoid the *-list-tests, since they reference a variable, leading to a problem
with --enable-shared.
* gettext-tools/libgettextpo/Makefile.am (config.h): Undefine GNULIB_GETCWD and
REPLACE_FCHDIR that are defined in the parent config.h.
