AS_EXECUTABLE_P again -- summary (was: bug in texi2dvi, and hack patch)

[Stepan Kasal]

Hello,

let me post a summary of the thread ``AS_EXECUTABLE_P again'' which
I started on the autoconf list:

I proposed to change the implementation of AS_EXECUTABLE_P on platforms
supporting `test -x' from
       test -f $1 && test -x $1
to
       test -x $1 && test ! -d $1

But Paul has pointed out the change can bring problems eg. with named
pipes in /tmp (some people have /tmp in their path).

Besides this, the benefit of this would be very limited:
1) Autoconf uses $ac_executable_extensions.  (This mechanism is fairly
general--if you want to recognize ruby scripts, all you need is to
add .rb to ac_executable_extensions in your config.site.)
2) On Cygwin, both `test -x foo' and `test -f foo' look for foo.exe.

Thus only a non-autoconf m4sh script running on DJGPP could benefit from
the proposed change.

I see two options:
- change DJGPP's `test -f foo' to search also for foo.exe
        (as suggested by Paul)
- make a DJGPP-specific change to AS_EXECUTABLE_P

But I don't think any of them is worth the time it would take.

Thanks,
        Stepan