On darwin, uniq can not take the flags -cd together, thanks to Ralf
for the fix, also ar does not accept N, so we use the fact that
ar x libfoo.a foo.o will always extract the first foo.o in the
archive and we then delete foo.o from the archive, which will also
delete only the first foo.o, then rinse and repeat. Also add markers
for the testuite.
* m4/libtool.m4 (_LT_CONFIG): Add a marker so that we can use a sed
expression to find the shell functions in libtool.
* tests/functests.at: Test this feature.
* tests/testsuite.at: Add the test.
* tests/Makefile.am: Add the test.
