diff --git a/acinclude.m4 b/acinclude.m4
index 5468447..e095fe1 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -15,7 +15,7 @@
 
 AC_DEFUN([PM_ENABLE],[
   AC_ARG_ENABLE($1,
-                AC_HELP_STRING([--disable-$1], [Disable pam_$1]),
+                AS_HELP_STRING([--disable-$1], [Disable pam_$1]),
                 [build_$1=$enableval],
 		[build_$1=m4_if([$2],[],yes,probe)])
   m4_pushdef([upmodname],translit($1, [a-z.-], [A-Z__]))
diff --git a/configure.ac b/configure.ac
index a6cf93e..f0a5c5e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -14,14 +14,14 @@
 # You should have received a copy of the GNU General Public License along
 # with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-AC_PREREQ(2.63)
+AC_PREREQ([2.71])
 
-AC_INIT(pam-modules, 2.5.90, bug-pam-modules@gnu.org.ua)
+AC_INIT([pam-modules],[2.5.90],[bug-pam-modules@gnu.org.ua])
 AC_CONFIG_SRCDIR(pam_fshadow/pam_fshadow.c)
 AC_CONFIG_AUX_DIR([build-aux])
 AC_CONFIG_MACRO_DIR([m4])
-AM_INIT_AUTOMAKE([1.11 no-exeext tar-ustar dist-xz silent-rules subdir-objects])
-AM_CONFIG_HEADER(config.h)
+AM_INIT_AUTOMAKE([1.16.5 no-exeext tar-ustar dist-xz silent-rules subdir-objects])
+AC_CONFIG_HEADERS([config.h])
 
 # Enable silent rules by default:
 AM_SILENT_RULES([yes])
@@ -35,7 +35,7 @@ dnl Checks for programs.
 AC_PROG_CC
 AC_PROG_INSTALL
 
-AM_DISABLE_STATIC
+AC_DISABLE_STATIC([])
 LT_PREREQ(2.2.5a)
 LT_INIT
 
@@ -44,7 +44,7 @@ AC_CHECK_LIB(pam, pam_get_item,:,
 		  [AC_MSG_ERROR([Required library libpam is not found])])
 
 AC_ARG_WITH(crypt-lib,
-            AC_HELP_STRING([--with-crypt-lib=LIB],
+            AS_HELP_STRING([--with-crypt-lib=LIB],
 	                   [use -lLIB instead of -lcrypt]),
 	    [cryptlib=$withval],
 	    [cryptlib=crypt])	
@@ -59,7 +59,6 @@ AC_CHECK_LIB(pam_misc, pam_misc_setenv,
 	      AC_DEFINE([HAVE_PAM_MISC_SETENV],1)],:,[-lpam])
 
 dnl Checks for header files.
-AC_HEADER_STDC
 AC_CHECK_HEADERS(security/pam_appl.h security/pam_modules.h,
                  :,
 		 AC_MSG_ERROR([Required PAM header files not found]))
@@ -89,20 +88,20 @@ PM_ENABLE(groupmember)
 # Check for SQL support	      
 
 AC_ARG_WITH(mysql,
-            AC_HELP_STRING([--without-mysql],
+            AS_HELP_STRING([--without-mysql],
 	                   [Configure to work without MySQL]),
 	    [want_mysql=$withval])	
 AC_ARG_WITH(pgsql,
-            AC_HELP_STRING([--without-pgsql],
+            AS_HELP_STRING([--without-pgsql],
 	                   [Configure to work without Postgres]),
 	    [want_pgsql=$withval])
 AC_ARG_WITH(postgres,
-            AC_HELP_STRING([--without-postgres],
+            AS_HELP_STRING([--without-postgres],
 	                   [Same as --without-pgsql]),
  	    [want_pgsql=$withval])
 AC_ARG_WITH(sql,
- AC_HELP_STRING([--without-sql],
-	                   [Do not build SQL dependent modules]),
+ AS_HELP_STRING([--without-sql],
+                [Do not build SQL dependent modules]),
 	  [want_mysql=$withval	
 	   want_pgsql=$withval])	
 	   
@@ -188,15 +187,15 @@ esac])
 ## debugging support
 ## *****************
 AC_ARG_ENABLE(debug,                     
-    AC_HELP_STRING([--enable-debug], [enable debugging mode]),
+    AS_HELP_STRING([--enable-debug],[enable debugging mode]),
     [if test "$enableval" = yes; then
        if test "$GCC" = yes; then
 	 AC_MSG_CHECKING(whether gcc accepts -ggdb)
          save_CFLAGS=$CFLAGS
          CFLAGS="-ggdb -Wall"
-         AC_TRY_COMPILE([],void f(){},
-           AC_MSG_RESULT(yes),
-           [if test x"$ac_cv_prog_cc_g" = xyes; then
+         AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]], [[void f(){}]])],
+	   [AC_MSG_RESULT(yes)],
+	   [if test x"$ac_cv_prog_cc_g" = xyes; then
               CFLAGS="-g -Wall"
             else
               CFLAGS=
@@ -212,8 +211,7 @@ AC_ARG_ENABLE(debug,
 ## **************
 PAMDIR='$(prefix)/lib/security'
 AC_ARG_WITH(pamdir,
-	    AC_HELP_STRING([--with-pamdir=DIR],
-	                   [install PAM modiles in DIR (PREFIX/lib/security)]),
+	    AS_HELP_STRING([--with-pamdir=DIR],[install PAM modiles in DIR (PREFIX/lib/security)]),
 	    [PAMDIR=$withval])
 AC_SUBST(PAMDIR)
 
@@ -258,7 +256,7 @@ build_umotd=$build_umotd
 build_groupmember=$build_groupmember
 build_innetgr=$build_innetgr])
 		
-AC_OUTPUT(Makefile
+AC_CONFIG_FILES([Makefile
           doc/Makefile
 	  examples/Makefile
 	  lib/Makefile
@@ -270,4 +268,5 @@ AC_OUTPUT(Makefile
 	  pam_umotd/Makefile
 	  pam_groupmember/Makefile
 	  pam_innetgr/Makefile
-	  pamck/Makefile)
+	  pamck/Makefile])
+AC_OUTPUT