Changed --with-zeus configure option into --with-isapi, since its more
descriptive (and since there are now different ways to configure PHP+Zeus)

Added changes to environment variable manipulations, to support Zeus 3.3.8
and increase compatibility between Zeus/IIS/Apache. Now, URLs like
http://foo.org/file.php/a/b/c/d work correctly.
# While testing, it looks like IIS+ISAPI is mishandling URLs like the above.
# The PATH_TRANSLATED given by ISAPI includes the /a/b/c/d bit of the URL,
# so using this var to find the script file to open on disk will not work.
# We now use SCRIPT_FILENAME if it is present (in Zeus 3.3.8)
# IIS doesn't seem to set this variable, it might be necessary to mangle
# SCRIPT_NAME and APPL_PHYSICAL_PATH together?

# Using LD_RUN_PATH to let the libphp4.so library find other libraries.
# Surely there should be a better way, using -rpath? However, libtool
# seems to swallow any extra -rpath options given to the compiler.