autoupdate: replace old version of AC_INIT by the new one

- old AC_INIT by AC_INIT + AC_CONFIG_SRC_DIR
  https://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.72/autoconf.html#index-AC_005fINIT-3

diff --git a/configure.ac b/configure.ac
index 9f69d46e3247cc6d816cab911486c1b117e4cde3..326d469c0c6ffb1a454cefaa2efea2bb24d3baf0 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -32,7 +32,8 @@ m4_include([ltversion.m4])
 m4_include([lt~obsolete.m4])
 m4_include([config/isl.m4])
 
-AC_INIT(move-if-change)
+AC_INIT
+AC_CONFIG_SRCDIR([move-if-change])
 AC_DISABLE_OPTION_CHECKING
 
 progname=$0