diff --git a/acinclude.m4 b/acinclude.m4
index ac490b483..464c161e6 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -329,18 +329,12 @@ fi
 #
 AC_DEFUN([GNUPG_TIME_T_UNSIGNED],
   [ AC_CACHE_CHECK(whether time_t is unsigned, gnupg_cv_time_t_unsigned,
-     [AC_REQUIRE([AC_HEADER_TIME])dnl
-      AC_COMPILE_IFELSE([AC_LANG_BOOL_COMPILE_TRY(
+     [AC_COMPILE_IFELSE([AC_LANG_BOOL_COMPILE_TRY(
        [AC_INCLUDES_DEFAULT([])
-#if TIME_WITH_SYS_TIME
+#if HAVE_SYS_TIME_H
 # include <sys/time.h>
-# include <time.h>
 #else
-# if HAVE_SYS_TIME_H
-#  include <sys/time.h>
-# else
-#  include <time.h>
-# endif
+# include <time.h>
 #endif
 ],
        [((time_t)-1) < 0])],
diff --git a/configure.ac b/configure.ac
index d81be7df8..566c1ebf8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -19,8 +19,8 @@
 # along with this program; if not, see <https://www.gnu.org/licenses/>.
 
 # Process this file with autoconf to produce a configure script.
-AC_PREREQ([2.61])
-min_automake_version="1.14"
+AC_PREREQ([2.69])
+min_automake_version="1.16.3"
 
 # To build a release you need to create a tag with the version number
 # (git tag -s gnupg-2.n.m) and run "./autogen.sh --force".  Please
@@ -83,7 +83,7 @@ VERSION=$PACKAGE_VERSION
 
 AC_CONFIG_AUX_DIR([build-aux])
 AC_CONFIG_SRCDIR([sm/gpgsm.c])
-AC_CONFIG_HEADER([config.h])
+AC_CONFIG_HEADERS([config.h])
 AM_INIT_AUTOMAKE([serial-tests dist-bzip2 no-dist-gzip])
 AC_CANONICAL_HOST
 AB_INIT
@@ -1321,13 +1321,11 @@ fi
 # Checks for header files.
 #
 AC_MSG_NOTICE([checking for header files])
-AC_HEADER_STDC
-AC_CHECK_HEADERS([string.h unistd.h langinfo.h termio.h locale.h getopt.h \
-                  pty.h utmp.h pwd.h inttypes.h signal.h sys/select.h     \
-                  stdint.h signal.h util.h libutil.h termios.h \
+AC_CHECK_HEADERS([unistd.h langinfo.h termio.h locale.h \
+                  pwd.h inttypes.h signal.h sys/select.h sys/time.h \
+                  stdint.h signal.h termios.h \
                   ucred.h sys/ucred.h sys/sysmacros.h sys/mkdev.h])
 
-AC_HEADER_TIME
 
 
 #
@@ -1375,15 +1373,10 @@ AC_CHECK_SIZEOF(unsigned long long)
 AC_HEADER_TIME
 AC_CHECK_SIZEOF(time_t,,[[
 #include <stdio.h>
-#if TIME_WITH_SYS_TIME
+#ifdef HAVE_SYS_TIME_H
 # include <sys/time.h>
-# include <time.h>
 #else
-# if HAVE_SYS_TIME_H
-#  include <sys/time.h>
-# else
-#  include <time.h>
-# endif
+# include <time.h>
 #endif
 ]])
 GNUPG_TIME_T_UNSIGNED
diff --git a/dirmngr/dns.c b/dirmngr/dns.c
index 25d839a97..64deb5db7 100644
--- a/dirmngr/dns.c
+++ b/dirmngr/dns.c
@@ -56,7 +56,7 @@
 #include <ws2tcpip.h>
 typedef SOCKET socket_fd_t;
 #define STDCALL __stdcall
-#ifdef TIME_WITH_SYS_TIME
+#ifdef HAVE_SYS_TIME_H
 #include <sys/time.h>		/* gettimeofday(2) */
 #endif
 #else
diff --git a/m4/tar-ustar.m4 b/m4/tar-ustar.m4
index 4ae9e63aa..11c3b53ed 100644
--- a/m4/tar-ustar.m4
+++ b/m4/tar-ustar.m4
@@ -10,7 +10,7 @@ dnl the same distribution terms as the rest of that program.
 AC_DEFUN([GNUPG_CHECK_USTAR],
 [
   AC_ARG_WITH(tar,
-     AC_HELP_STRING([--with-tar=PATH],[look for a tar program in PATH]),
+     AS_HELP_STRING([--with-tar=PATH],[look for a tar program in PATH]),
      [_do_tar=$withval])
 
   if test x$_do_tar != xno ; then