m4: update various libraries from autoconf-archive 20170928

m4/ax_append_compile_flags.m4

-# ===========================================================================
-#  http://www.gnu.org/software/autoconf-archive/ax_append_compile_flags.html
-# ===========================================================================
+# ============================================================================
+#  https://www.gnu.org/software/autoconf-archive/ax_append_compile_flags.html
+# ============================================================================
 #
 # SYNOPSIS
 #
@@ -41,7 +41,7 @@
 #   Public License for more details.
 #
 #   You should have received a copy of the GNU General Public License along
-#   with this program. If not, see <http://www.gnu.org/licenses/>.
+#   with this program. If not, see <https://www.gnu.org/licenses/>.
 #
 #   As a special exception, the respective Autoconf Macro's copyright owner
 #   gives unlimited permission to copy, distribute and modify the configure
@@ -56,7 +56,7 @@
 #   modified version of the Autoconf Macro, you may extend this special
 #   exception to the GPL to apply to your modified version as well.
 
-#serial 5
+#serial 6
 
 AC_DEFUN([AX_APPEND_COMPILE_FLAGS],
 [AX_REQUIRE_DEFINED([AX_CHECK_COMPILE_FLAG])

m4/ax_append_flag.m4

 # ===========================================================================
-#      http://www.gnu.org/software/autoconf-archive/ax_append_flag.html
+#      https://www.gnu.org/software/autoconf-archive/ax_append_flag.html
 # ===========================================================================
 #
 # SYNOPSIS
@@ -34,7 +34,7 @@
 #   Public License for more details.
 #
 #   You should have received a copy of the GNU General Public License along
-#   with this program. If not, see <http://www.gnu.org/licenses/>.
+#   with this program. If not, see <https://www.gnu.org/licenses/>.
 #
 #   As a special exception, the respective Autoconf Macro's copyright owner
 #   gives unlimited permission to copy, distribute and modify the configure
@@ -49,7 +49,7 @@
 #   modified version of the Autoconf Macro, you may extend this special
 #   exception to the GPL to apply to your modified version as well.
 
-#serial 6
+#serial 7
 
 AC_DEFUN([AX_APPEND_FLAG],
 [dnl

m4/ax_append_link_flags.m4

 # ===========================================================================
-#   http://www.gnu.org/software/autoconf-archive/ax_append_link_flags.html
+#   https://www.gnu.org/software/autoconf-archive/ax_append_link_flags.html
 # ===========================================================================
 #
 # SYNOPSIS
@@ -39,7 +39,7 @@
 #   Public License for more details.
 #
 #   You should have received a copy of the GNU General Public License along
-#   with this program. If not, see <http://www.gnu.org/licenses/>.
+#   with this program. If not, see <https://www.gnu.org/licenses/>.
 #
 #   As a special exception, the respective Autoconf Macro's copyright owner
 #   gives unlimited permission to copy, distribute and modify the configure
@@ -54,7 +54,7 @@
 #   modified version of the Autoconf Macro, you may extend this special
 #   exception to the GPL to apply to your modified version as well.
 
-#serial 5
+#serial 6
 
 AC_DEFUN([AX_APPEND_LINK_FLAGS],
 [AX_REQUIRE_DEFINED([AX_CHECK_LINK_FLAG])

m4/ax_check_compile_flag.m4

 # ===========================================================================
-#   http://www.gnu.org/software/autoconf-archive/ax_check_compile_flag.html
+#  https://www.gnu.org/software/autoconf-archive/ax_check_compile_flag.html
 # ===========================================================================
 #
 # SYNOPSIS
@@ -40,7 +40,7 @@
 #   Public License for more details.
 #
 #   You should have received a copy of the GNU General Public License along
-#   with this program. If not, see <http://www.gnu.org/licenses/>.
+#   with this program. If not, see <https://www.gnu.org/licenses/>.
 #
 #   As a special exception, the respective Autoconf Macro's copyright owner
 #   gives unlimited permission to copy, distribute and modify the configure
@@ -55,7 +55,7 @@
 #   modified version of the Autoconf Macro, you may extend this special
 #   exception to the GPL to apply to your modified version as well.
 
-#serial 4
+#serial 5
 
 AC_DEFUN([AX_CHECK_COMPILE_FLAG],
 [AC_PREREQ(2.64)dnl for _AC_LANG_PREFIX and AS_VAR_IF

m4/ax_check_link_flag.m4

 # ===========================================================================
-#    http://www.gnu.org/software/autoconf-archive/ax_check_link_flag.html
+#    https://www.gnu.org/software/autoconf-archive/ax_check_link_flag.html
 # ===========================================================================
 #
 # SYNOPSIS
@@ -40,7 +40,7 @@
 #   Public License for more details.
 #
 #   You should have received a copy of the GNU General Public License along
-#   with this program. If not, see <http://www.gnu.org/licenses/>.
+#   with this program. If not, see <https://www.gnu.org/licenses/>.
 #
 #   As a special exception, the respective Autoconf Macro's copyright owner
 #   gives unlimited permission to copy, distribute and modify the configure
@@ -55,7 +55,7 @@
 #   modified version of the Autoconf Macro, you may extend this special
 #   exception to the GPL to apply to your modified version as well.
 
-#serial 4
+#serial 5
 
 AC_DEFUN([AX_CHECK_LINK_FLAG],
 [AC_PREREQ(2.64)dnl for _AC_LANG_PREFIX and AS_VAR_IF

m4/ax_cxx_compile_stdcxx_14.m4

-# ============================================================================
-#  http://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx_14.html
-# ============================================================================
+# =============================================================================
+#  https://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx_14.html
+# =============================================================================
 #
 # SYNOPSIS
 #
@@ -28,7 +28,7 @@
 #   and this notice are preserved. This file is offered as-is, without any
 #   warranty.
 
-#serial 4
+#serial 5
 
 AX_REQUIRE_DEFINED([AX_CXX_COMPILE_STDCXX])
 AC_DEFUN([AX_CXX_COMPILE_STDCXX_14], [AX_CXX_COMPILE_STDCXX([14], [$1], [$2])])

m4/ax_pthread.m4

 # ===========================================================================
-#        http://www.gnu.org/software/autoconf-archive/ax_pthread.html
+#        https://www.gnu.org/software/autoconf-archive/ax_pthread.html
 # ===========================================================================
 #
 # SYNOPSIS
@@ -67,7 +67,7 @@
 #   Public License for more details.
 #
 #   You should have received a copy of the GNU General Public License along
-#   with this program. If not, see <http://www.gnu.org/licenses/>.
+#   with this program. If not, see <https://www.gnu.org/licenses/>.
 #
 #   As a special exception, the respective Autoconf Macro's copyright owner
 #   gives unlimited permission to copy, distribute and modify the configure
@@ -82,7 +82,7 @@
 #   modified version of the Autoconf Macro, you may extend this special
 #   exception to the GPL to apply to your modified version as well.
 
-#serial 23
+#serial 24
 
 AU_ALIAS([ACX_PTHREAD], [AX_PTHREAD])
 AC_DEFUN([AX_PTHREAD], [

m4/ax_require_defined.m4

 # ===========================================================================
-#    http://www.gnu.org/software/autoconf-archive/ax_require_defined.html
+#    https://www.gnu.org/software/autoconf-archive/ax_require_defined.html
 # ===========================================================================
 #
 # SYNOPSIS
@@ -30,7 +30,7 @@
 #   and this notice are preserved. This file is offered as-is, without any
 #   warranty.
 
-#serial 1
+#serial 2
 
 AC_DEFUN([AX_REQUIRE_DEFINED], [dnl
   m4_ifndef([$1], [m4_fatal([macro ]$1[ is not defined; is a m4 file missing?])])