libsystemd: new library, refactor sd-daemon.[ch] test code

This commit introduces a bare-bones replacement for libsystemd:

 - Build .so file and add --with-libsystemd to configure
 - Add capabilities support to test/src/serv.c
 - Update tests to account for a Finit built w/o libsystemd support

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

src/Makefile.am

@@ -9,6 +9,7 @@ endif
 
 sbin_PROGRAMS        = finit initctl
 pkglibexec_PROGRAMS  = getty logit runparts tmpfiles
+
 if SULOGIN
 pkglibexec_PROGRAMS += sulogin
 endif