bug#29931: 27.0.50; Slightly suboptimal build behavior on macOS

[Alan Third]

On Tue, Jan 02, 2018 at 10:04:37PM +0200, Eli Zaretskii wrote:
> > From: Philipp Stephani <p.stephani2@gmail.com>
> > Date: Tue, 02 Jan 2018 19:48:45 +0000
> > Cc: 29931@debbugs.gnu.org
> > 
> > Maybe just do 'test -x /.../makeinfo' to test for the file directly? 
> 
> ISTR that the -x switch to 'test' is non-portable.

I’m not sure how portable this test needs to be since it should only
run on darwin:

    if test "${opsys}" = darwin && test -z "${MAKEINFO}" && \
       test -x /usr/local/opt/texinfo/bin/makeinfo; then

-- 
Alan Third