not portable to other @command{make} implementations.
The only way Automake could support @command{$(wildcard ...)} is by
-expending @command{$(wildcard ...)} when @command{automake} is run.
+expanding @command{$(wildcard ...)} when @command{automake} is run.
The resulting @file{Makefile.in}s would be portable since they would
list all files and not use @samp{$(wildcard ...)}. However that
means developers would need to remember to run @command{automake} each