Augmented path checks do not work as advertised

[David Kastrup]

This is autoconf 2.53.  The manual states:

Generic Program and File Checks
-------------------------------

   These macros are used to find programs not covered by the
"particular" test macros.  If you need to check the behavior of a
program as well as find out whether it is present, you have to write
your own test for it (see *note Writing Tests::).  By default, these macros
use the environment variable `PATH'.  If you need to check for a
program that might not be in the user's `PATH', you can pass a
modified path to use instead, like this:

     AC_PATH_PROG([INETD], [inetd], [/usr/libexec/inetd],
                  [$PATH:/usr/libexec:/usr/sbin:/usr/etc:etc])


This does not work, however, since the configure script does some
stupid trickery for the sake of making PATH have some different
separator, and then : is not recognized as a separator any more.

What would be a way portable across a reasonable subset of autoconf
versions to achieve the above?

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum