diff --git a/configure.ac b/configure.ac
index 313793bf..1414f063 100644
--- a/configure.ac
+++ b/configure.ac
@@ -17,7 +17,7 @@ AC_INIT(src/WindowMaker.h)
 
 AM_INIT_AUTOMAKE(WindowMaker, 0.70.0)
 
-AC_PROG_LIBTOOL
+AM_PROG_LIBTOOL
 
 # by Marcelo Magallon <mmagallo@efis.ucr.ac.cr>
 # Turn around -rpath problem with libtool 1.0c
diff --git a/configure.in b/configure.in
index 313793bf..1414f063 100644
--- a/configure.in
+++ b/configure.in
@@ -17,7 +17,7 @@ AC_INIT(src/WindowMaker.h)
 
 AM_INIT_AUTOMAKE(WindowMaker, 0.70.0)
 
-AC_PROG_LIBTOOL
+AM_PROG_LIBTOOL
 
 # by Marcelo Magallon <mmagallo@efis.ucr.ac.cr>
 # Turn around -rpath problem with libtool 1.0c