Fix: configure: support Autoconf 2.70
This patch is stolen and adapted from lttng-tools' patch:
https://git.lttng.org/?p=lttng-tools.git;a=commit;h=
faa88ea855741f5c356d223011ff4b347576c7d2
The newly-released autoconf 2.70 introduces a number of breaking
changes [1] and is being rolled-out by some distros.
Amongst those changes, the AC_PROG_CC_STDC macro is marked as obsolete
and was merged into AC_PROG_CC, which we already use. On 2.70, this
results in a warning which we handle as an error.
A version check is added to invoke the AC_PROG_CC_STDC macro only when
running a pre-2.70 version of autoconf, fixing the issue.
The AC_PROG_LEX now takes an argument, and the argument-less version is
marked as obsolete. The macro is invoked with the `noyywrap` option, as
recommended in the documentation.
Also, the AX_PTHREAD macro makes use of the $as_echo built-in shell
variable which no longer exists in 2.70. A patch was submitted to the
GNU Autoconf archive in March, but there have been no signs of life
given since then [2].
As such, our local copy is updated to the latest version and the patch
(which looks fairly straight-forward / safe) is applied. This should
minimize changes once we go back to an "official" version of the macro.
Some issues with glib2 remain:
configure.ac:264: warning: The macro `AC_TRY_RUN' is obsolete.
configure.ac:264: You should run autoupdate.
./lib/autoconf/general.m4:2996: AC_TRY_RUN is expanded from...
/usr/share/aclocal/glib-2.0.m4:11: AM_PATH_GLIB_2_0 is expanded from...
configure.ac:264: the top level
configure.ac:264: warning: The macro `AC_TRY_LINK' is obsolete.
configure.ac:264: You should run autoupdate.
./lib/autoconf/general.m4:2919: AC_TRY_LINK is expanded from...
/usr/share/aclocal/glib-2.0.m4:11: AM_PATH_GLIB_2_0 is expanded from...
configure.ac:264: the top level
Those have been fixed upstream:
https://gitlab.gnome.org/GNOME/glib/-/commit/
6f26637e83727b05f865389937bb07c761c13c12
so it's always possible to get the modifications from there for local
development.
[1] https://lwn.net/Articles/839395/
[2] https://savannah.gnu.org/patch/?9906
Change-Id: I484b2caed1c7e89e100be76b7853099239397012
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>