Obselete Autoconf macros
When regenerating configure script with autoconf-2.71, I can see these warnings:
configure.ac:71: warning: The macro `AC_HEADER_STDC' is obsolete.
configure.ac:71: You should run autoupdate.
./lib/autoconf/headers.m4:704: AC_HEADER_STDC is expanded from...
configure.ac:71: the top level
configure.ac:72: warning: The macro `AC_HEADER_TIME' is obsolete.
configure.ac:72: You should run autoupdate.
./lib/autoconf/headers.m4:743: AC_HEADER_TIME is expanded from...
configure.ac:72: the top level
configure.ac:118: warning: The macro `ACX_PTHREAD' is obsolete.
configure.ac:118: You should run autoupdate.
aclocal.m4:266: ACX_PTHREAD is expanded from...
configure.ac:118: the top level
From Autoconf documentation:
-- Macro: AC_HEADER_STDC
This macro is obsolescent. Its sole effect is to make sure that
all the headers that are included by ‘AC_INCLUDES_DEFAULT’ (*note
Default Includes::), but not part of ISO C90, have been checked
for.
All hosted environments that are still of interest for portable
code provide all of the headers specified in ISO C90 (as amended in
1995).
-- Macro: AC_HEADER_TIME
This macro used to check whether it was possible to include
‘time.h’ and ‘sys/time.h’ in the same source file, defining
‘TIME_WITH_SYS_TIME’ if so.
Nowadays, it is equivalent to ‘AC_CHECK_HEADERS([sys/time.h])’,
although it does still define ‘TIME_WITH_SYS_TIME’ for
compatibility’s sake. ‘time.h’ is universally present, and the
systems on which ‘sys/time.h’ conflicted with ‘time.h’ are
obsolete.
ACX_PTHREAD was renamed to AX_PTHREAD as can be found in ax_pthread.m4 of autoconf-archive-2022.09.03.