daemon: use gnulib

daemon: use gnulib

* daemon/Makefile.am (SUBDIRS): Define.
(AM_CPPFLAGS): Define, to include from gnulib's lib/
(LDADD): Define, to link with gnulib's libgnu.a.
* daemon/configure.ac: Use AC_CONFIG_AUX_DIR([build-aux]),
gl_EARLY and gl_INIT.
(AC_CONFIG_FILES): Add lib/Makefile and tests/Makefile
* daemon/m4/gnulib-cache.m4: New file, generated by running
../.gnulib/gnulib-tool --import --with-tests hash
* daemon/.gitignore: Ignore all of the imported files.
build: tell bootstrap about daemon/
* bootstrap: Run gnulib-tool --update in daemon/.
Remove bootstrap's --gnulib-srcdir option, because it probably
didn't work, and even if it did, we've discovered that using
a separate git repo like that can lead to subtle mix-ups.