How I pipe lists into ifnames

[Ted Bagg]

The version of ifnames that comes with Autoconf 2.13 doesn't actually read 
lists of filenames piped in, despite doc to the contrary in the ifnames 
header comments and in the Autoconf info docs.  The workaround that seems 
best to me is
        ... | (ifnames `cat -`)
although one might add code (seems a waste, really) to ifnames instead.