Add Makefile.in so that configure can determine if inet_aton.o is required

Add Makefile.in so that configure can determine if inet_aton.o is required

Add CFLAGS= @CPPFLAGS@ to Makefile.global and configure so that build is
	useful for finding extra header files

Split header files from libraries in build.  Doesn't make much sense to
	look for a header file in /usr/local/lib, nor to look for a library
	in /usr/local/include :)