Enable more features at distcheck for improved coverage

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

Makefile.am

@@ -30,4 +30,6 @@ release: distcheck
 		printf "$$file.sha256\t"; cat ../$$file.sha256 | cut -f1 -d' ';	\
 	done
 
-DISTCHECK_CONFIGURE_FLAGS = --with-fstab=/etc/fstab
+DISTCHECK_CONFIGURE_FLAGS = --prefix=/usr --sysconfdir=/etc --localstatedir=/var \
+			    --enable-testserv-plugin --enable-x11-common-plugin  \
+			    --with-watchdog --with-keventd --with-fstab=/etc/fstab