Add gnulib-tool unit tests.

* bootstrap: Re-add --with-tests, now that gnulib-tool
arranges to use separate libraries for lib/ and tests/.
* configure.in (AC_OUTPUT): Add gnulib/tests/Makefile.in.
* Makefile.am (SUBDIRS): Add gnulib/tests.
* gnulib/tests/Makefile.am: New file.
* gnulib/lib/.cvsignore: Sort.
* gnulib/lib/Makefile.am, gnulib/m4/getdelim.m4, gnulib/m4/getline.m4:
* gnulib/m4/gnulib-cache.m4, gnulib/m4/gnulib-comp.m4: Regenerate.
* gnulib/tests/test-alloca-opt.c: New file, from gnulib.
* gnulib/tests/test-arpa_inet.c: Likewise.
* gnulib/tests/test-fseeko.c: Likewise.
* gnulib/tests/test-fseeko.sh: Likewise.
* gnulib/tests/test-getaddrinfo.c: Likewise.
* gnulib/tests/test-getdelim.c: Likewise.
* gnulib/tests/test-getline.c: Likewise.
* gnulib/tests/test-lseek.c: Likewise.
* gnulib/tests/test-lseek.sh: Likewise.
* gnulib/tests/test-netinet_in.c: Likewise.
* gnulib/tests/test-snprintf.c: Likewise.
* gnulib/tests/test-stdbool.c: Likewise.
* gnulib/tests/test-stdint.c: Likewise.
* gnulib/tests/test-stdio.c: Likewise.
* gnulib/tests/test-stdlib.c: Likewise.
* gnulib/tests/test-string.c: Likewise.
* gnulib/tests/test-sys_select.c: Likewise.
* gnulib/tests/test-sys_socket.c: Likewise.
* gnulib/tests/test-sys_stat.c: Likewise.
* gnulib/tests/test-sys_time.c: Likewise.
* gnulib/tests/test-unistd.c: Likewise.
* gnulib/tests/test-vasnprintf.c: Likewise.
* gnulib/tests/test-vasprintf.c: Likewise.
* gnulib/tests/test-wchar.c: Likewise.
* gnulib/tests/dummy.c: Likewise.
* gnulib/tests/intprops.h: Likewise.
* gnulib/tests/verify.h: Likewise.

bootstrap

@@ -71,6 +71,7 @@ gnulib_tool=$GNULIB_SRCDIR/gnulib-tool
 
 $gnulib_tool			\
   --lgpl=2			\
+  --with-tests			\
   --m4-base=gnulib/m4		\
   --source-base=gnulib/lib	\
   --tests-base=gnulib/tests	\