Savannah bug #31424: Revert Interix-specific change.

Gnulib will use suacomp for solving this problem, so findutils
will not need a workaround here.
* lib/arg-max.h: Delete this file.
* lib/Makefile.am (libfind_a_SOURCES): Remove arg-max.h.
* lib/buildcmd.c: Don't include arg-max.h.
* xargs/xargs.c: Likewise.

lib/buildcmd.c

@@ -71,7 +71,6 @@
 
 #include "xstrtol.h"
 #include "buildcmd.h"
-#include "arg-max.h"		/* must include after unistd.h. */
 
 
 extern char **environ;