This change fixes spurious failures of the tests ar-lib4.test,
ar-lib6a.test and ar-lib6b.test.
* tests/Makefile.am (ar-lib4.log): Depend explicitly on the
`libtool-macros.log' file.
(ar-lib6a.log, ar-lib6b.log): Likewise.
# FIXME: make these automatically computed once we are merged into
# FIXME: the `testsuite-work' branch.
+ar-lib4.log: libtool-macros.log
+ar-lib6a.log: libtool-macros.log
+ar-lib6b.log: libtool-macros.log
depcomp4.log: libtool-macros.log
depcomp7.log: libtool-macros.log
depcomp8b.log: libtool-macros.log