autoupdate: replace obsolete macros AC_PROG_LIBTOOL

- AC_PROG_LIBTOOL by LT_INIT
  https://www.gnu.org/software/libtool/manual/html_node/LT_005fINIT.html#index-LT_005fINIT

diff --git a/zlib/configure.ac b/zlib/configure.ac
index b50b9c7b42617344793d2999e48da0b4b2bede9e..fa1c8fedd6b1a44fbaeec03c9f679c1248c0d292 100644 (file)
--- a/zlib/configure.ac
+++ b/zlib/configure.ac
@@ -60,7 +60,7 @@ m4_rename_force([real_PRECIOUS],[_AC_ARG_VAR_PRECIOUS])
 
 AC_SUBST(CFLAGS)
 
-AC_PROG_LIBTOOL
+LT_INIT
 
 # Find CPP now so that any conditional tests below won't do it and
 # thereby make the resulting definitions conditional.