USE_TOOLS and any of "autoconf", "autoconf213", "automake" or
"automake14". Also, we don't need to call the auto* tools via
${ACLOCAL}, ${AUTOCONF}, etc., since the tools framework takes care
to symlink the correct tool to the correct name, so we can just use
aclocal, autoconf, etc.
Netscape Portable Runtime (NSPR) provides a platform-neutral API for system
level and libc like functions. The API is used in the Mozilla client, many of
Netscape/AOL/iPlanet's and other software offerings.