build: add a common.am include file and a "make lolcheck" target that does

nothing for now except ensure that every makefile includes common.am.

neercs/Makefile.am

@@ -1,4 +1,6 @@
 
+include $(top_srcdir)/build/autotools/common.am
+
 if BUILD_NEERCS
 noinst_PROGRAMS = neercs
 endif