Hi all: Macro AC_PROG_CC_C99 is obsolete as of Autoconf version 2.70 . Projects like OpenOCD are resorting to this kind of workaround: m4_version_prereq([2.70],[],[AC_PROG_CC_C99]) You can see it here: https://sourceforge.net/p/openocd/code/ci/master/tree/configure.ac Other projects are doing similar things, see for example the discussion here: https://gitlab.torproject.org/tpo/core/tor/-/merge_requests/355 The interesting statement there is: "neither including AC_PROG_CC_C99 macro nor leaving it out will give you the right behavior with both [Autoconf 2.69 and 2.70] versions" The trouble is, with the m4_version_prereq solution mentioned above, I am still getting the following warning, at least with OpenOCD and Autoconf 2.71: configure.ac:38: warning: The macro `AC_PROG_CC_C99' is obsolete. configure.ac:38: You should run autoupdate. /home/rdiez/[...blah blah...]/autoconf/c.m4:1659: AC_PROG_CC_C99 is expanded from... configure.ac:38: the top level I am no Autoconf guru. Is there a way to conditionally use AC_PROG_CC_C99 so that it does not generate such an "obsolete" warning? Many systems are still using Autoconf 2.69, and will probably continue to do so for quite some time. Thanks in advance, rdiez
