Use fsock.c from my module

In order to keep my network interface portable I thought it better to write using fsock.c and require that sockets be enabled for php. Is this advisable? In my config.m4 how do I check that --enable-sockets is active? In my config.m4 how do I cause to be defined somewhere one of the PATHS calculated by config.m4 - in order that my C module knows the compile time paths as defaults for other things. Thanks Sam