Fixed building of libfcgi when PHP is built from another directory.
Added missing headers needed for wait().
Removed duplicate signal.h header.
Removed unneeded variables.
include fastcgi library for ease of windows builds
NOTE: included fastcgi library is modified for thread safety, but
fastcgi support in cgi_main.c is only written for single
threaded serving. This does not present any issue for using
fastcgi.