unprefixed header guards

[Bruce Korb]

As of now, here are the files that get installed via "libposix":

$ find * -type f
usr/local/lib/libposix.a
usr/local/lib/libposix.so.0.0.0
usr/local/lib/libposix.la
[[a mess of includes]]
usr/local/libexec/libposix/pt_chown

And here are the headers that do not prefix an "ifndef"
with "_LIBPOSIX_":

$ ls -1 $(allbut usr/local/include/*.h - $(
> egrep -l '#ifndef _LIBPOSIX_' usr/local/include/*.h) )
usr/local/include/arg-nonnull.h
usr/local/include/iconv_open-aix.h
usr/local/include/iconv_open-hpux.h
usr/local/include/iconv_open-irix.h
usr/local/include/iconv_open-osf.h
usr/local/include/iconv_open-solaris.h
usr/local/include/inttypes.h
usr/local/include/unitypes.h
usr/local/include/unused-parameter.h
usr/local/include/warn-on-use.h

The "iconv_open" ones are private and clearly okay.
However, arg-nonnull.h:
#ifndef _GL_ARG_NONNULL

and inttypes.h looks very strange:
/* The definition of _GL_WARN_ON_USE is copied here.  */
#ifndef _GL_WARN_ON_USE

unitypes.h:
#ifndef _UNITYPES_H
#define _UNITYPES_H

unused-parameter.h:
#ifndef _GL_UNUSED_PARAMETER

and warn-on-use uses _GL_WARN_ON_USE, per the copied text in inttypes.h

I don't know the plan here, but it isn't consistent.

Thanks - Bruce