The name "aux" is reserved on Windows platforms, a legacy from CP/M
via MS-DOS. Rename it to "helpers".
Turns out that that directory wasn't actually used properly, because
AC_CONFIG_AUX_DIR was never defined, and there was a redundant copy of
install-sh checked into the base of the source tree.
Reported-by: Ehsan Alem Mohammad Ghasemlou <e.ghasemloo@gmail.com>
NASM-Bugzilla: https://bugzilla.nasm.us/show_bug.cgi?id=3392560
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
