Fix --with-tests compilation on cygwin.

Fix --with-tests compilation on cygwin.
* modules/argmatch-tests (Makefile.am): List gnulib library first
in LDADD.
* modules/argp-tests (Makefile.am): Likewise.
* modules/array-list-tests (Makefile.am): Likewise.
* modules/array-oset-tests (Makefile.am): Likewise.
* modules/avltree-list-tests (Makefile.am): Likewise.
* modules/avltree-oset-tests (Makefile.am): Likewise.
* modules/avltreehash-list-tests (Makefile.am): Likewise.
* modules/carray-list-tests (Makefile.am): Likewise.
* modules/dirname-tests (Makefile.am): Likewise.
* modules/frexp-tests (Makefile.am): Likewise.
* modules/isnanl-tests (Makefile.am): Likewise.
* modules/linked-list-tests (Makefile.am): Likewise.
* modules/linkedhash-list-tests (Makefile.am): Likewise.
* modules/lock-tests (Makefile.am): Likewise.
* modules/rbtree-list-tests (Makefile.am): Likewise.
* modules/rbtree-oset-tests (Makefile.am): Likewise.
* modules/rbtreehash-list-tests (Makefile.am): Likewise.
* modules/tls-tests (Makefile.am): Likewise.
* modules/tsearch-tests (Makefile.am): Likewise.
* modules/xvasprintf-tests (Makefile.am): Likewise.