And fix the macro's spelling, too :)
QF_PROCESS_NEED_subroutine needs too much knowledge to get the prefix
riight every time. Much easier to set it at invocation.
QF_PROCESS_NEED has been renamed to QF_PROCESS_NEED_LIBS and its guts have
been moved to QF_PROCESS_NEED_subroutine, with additional modifications to
allow QF_NEED to be used for other targets as well (eg, directories,
executables, etc).