Idea to support 'test -x' for AS_EXECUTABLE_P again

[Sander Niemeijer]

It seems that in the _AS_TEST_PREPARE part of the m4sugar/m4sh.m4 file, 
as_executable_p is not set to 'test -x' if this can be done. An old 
seemingly 'buggy' version was renamed to _AS_BROKEN_TEST_PREPARE.
I was wondering whether the old test can't be rewritten to test 
executability of '/bin/sh' (which is always available and executable, 
right?). This would turn it into something like:

---
m4_defun([_AS_TEST_PREPARE],
[if test -x /bin/sh >/dev/null 2>&1; then
  as_executable_p="test -x"
elif test -f /bin/sh >/dev/null 2>&1; then
  as_executable_p="test -f"
else
  AS_ERROR([cannot check whether a file is executable on this system])
fi
])# _AS_TEST_PREPARE
---

Anybody got any idea whether this is a portable solution?

Regards,
Sander