Version number constructed with m4_esyscmd not a literal?

[Marko Lindqvist]

Freeciv ( http://www.freeciv.org ) configure.ac has AC_INIT like this:

AC_INIT([freeciv], [m4_esyscmd([./fc_version | tr -d '\n'])])


This results in warnings from aclocal, autoheader, autoconf and automake:
configure.ac:5: warning: AC_INIT: not a literal:
m4_esyscmd([./fc_version | tr -d '\n'])

Resulting configure seems to work correctly, and it even has correct line
# Generated by GNU Autoconf 2.68 for freeciv 2.3.99-dev
in it.


What is wrong with our AC_INIT? I've seen use of m4_esyscmd
recommended for similar cases in this list, so I assume it can be
somehow used without such warning.


 - ML