Remove unused m4 macros and update AX_PTHREAD

Remove the unused AX_CHECK_LIBRARY and REQUIRE_CANONICAL macros from m4/, and stop calling AC_CANONICAL_TARGET from configure.ac since this tree no longer needs target canonicalization.

Update m4/ax_pthread.m4 to the latest AX_PTHREAD macro from the autoconf archive, which brings the host-based canonicalization checks used by the current upstream macro.

configure.ac

@@ -25,7 +25,6 @@ CFLAGS="$CFLAGS $C_EXTRA_FLAGS $C_FLAGS"
 AC_PROG_CC
 AM_PROG_CC_C_O
 AC_CANONICAL_HOST
-AC_CANONICAL_TARGET
 AC_CONFIG_MACRO_DIR([m4])
 
 AM_INIT_AUTOMAKE([1.13.4 -Wall -Werror -Wno-portability foreign tar-ustar subdir-objects no-define color-tests])

m4/ax_check_library.m4

@@ -1,95 +0,0 @@
-# ===========================================================================
-#     https://www.gnu.org/software/autoconf-archive/ax_check_library.html
-# ===========================================================================
-#
-# SYNOPSIS
-#
-#   AX_CHECK_LIBRARY(VARIABLE-PREFIX, HEADER-FILE, LIBRARY-FILE,
-#                    [ACTION-IF-FOUND], [ACTION-IF-NOT_FOUND])
-#
-# DESCRIPTION
-#
-#   Provides a generic test for a given library, similar in concept to the
-#   PKG_CHECK_MODULES macro used by pkg-config.
-#
-#   Most simplest libraries can be checked against simply through the
-#   presence of a header file and a library to link to. This macro allows to
-#   wrap around the test so that it doesn't have to be recreated each time.
-#
-#   Rather than define --with-$LIBRARY arguments, it uses variables in the
-#   same way that PKG_CHECK_MODULES does. It doesn't, though, use the same
-#   names, since you shouldn't provide a value for LIBS or CFLAGS but rather
-#   for LDFLAGS and CPPFLAGS, to tell the linker and compiler where to find
-#   libraries and headers respectively.
-#
-#   If the library is find, HAVE_PREFIX is defined, and in all cases
-#   PREFIX_LDFLAGS and PREFIX_CPPFLAGS are substituted.
-#
-#   Example:
-#
-#     AX_CHECK_LIBRARY([LIBEVENT], [event.h], [event], [],
-#                      [AC_MSG_ERROR([Unable to find libevent])])
-#
-# LICENSE
-#
-#   Copyright (c) 2010 Diego Elio Petteno` <flameeyes@gmail.com>
-#
-#   This program is free software: you can redistribute it and/or modify it
-#   under the terms of the GNU General Public License as published by the
-#   Free Software Foundation, either version 3 of the License, or (at your
-#   option) any later version.
-#
-#   This program is distributed in the hope that it will be useful, but
-#   WITHOUT ANY WARRANTY; without even the implied warranty of
-#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
-#   Public License for more details.
-#
-#   You should have received a copy of the GNU General Public License along
-#   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
-#   scripts that are the output of Autoconf when processing the Macro. You
-#   need not follow the terms of the GNU General Public License when using
-#   or distributing such scripts, even though portions of the text of the
-#   Macro appear in them. The GNU General Public License (GPL) does govern
-#   all other use of the material that constitutes the Autoconf Macro.
-#
-#   This special exception to the GPL applies to versions of the Autoconf
-#   Macro released by the Autoconf Archive. When you make and distribute a
-#   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
-
-AC_DEFUN([AX_CHECK_LIBRARY], [
-  AC_ARG_VAR($1[_CPPFLAGS], [C preprocessor flags for ]$1[ headers])
-  AC_ARG_VAR($1[_LDFLAGS], [linker flags for ]$1[ libraries])
-
-  AC_CACHE_VAL(AS_TR_SH([ax_cv_have_]$1),
-    [save_CPPFLAGS="$CPPFLAGS"
-     save_LDFLAGS="$LDFLAGS"
-     save_LIBS="$LIBS"
-
-     AS_IF([test "x$]$1[_CPPFLAGS" != "x"],
-       [CPPFLAGS="$CPPFLAGS $]$1[_CPPFLAGS"])
-
-     AS_IF([test "x$]$1[_LDFLAGS" != "x"],
-       [LDFLAGS="$LDFLAGS $]$1[_LDFLAGS"])
-
-     AC_CHECK_HEADER($2, [
-       AC_CHECK_LIB($3, [main],
-         [AS_TR_SH([ax_cv_have_]$1)=yes],
-         [AS_TR_SH([ax_cv_have_]$1)=no])
-     ], [AS_TR_SH([ax_cv_have_]$1)=no])
-
-     CPPFLAGS="$save_CPPFLAGS"
-     LDFLAGS="$save_LDFLAGS"
-     LIBS="$save_LIBS"
-    ])
-
-  AS_IF([test "$]AS_TR_SH([ax_cv_have_]$1)[" = "yes"],
-    AC_DEFINE([HAVE_]$1, [1], [Define to 1 if ]$1[ is found])
-    [$4],
-    [$5])
-])

m4/ax_pthread.m4

@@ -87,11 +87,11 @@
 #   modified version of the Autoconf Macro, you may extend this special
 #   exception to the GPL to apply to your modified version as well.
 
-#serial 30
+#serial 31
 
 AU_ALIAS([ACX_PTHREAD], [AX_PTHREAD])
 AC_DEFUN([AX_PTHREAD], [
-AC_REQUIRE([AC_CANONICAL_TARGET])
+AC_REQUIRE([AC_CANONICAL_HOST])
 AC_REQUIRE([AC_PROG_CC])
 AC_REQUIRE([AC_PROG_SED])
 AC_LANG_PUSH([C])
@@ -158,7 +158,7 @@ ax_pthread_flags="pthreads none -Kthread -pthread -pthreads -mthreads pthread --
 # --thread-safe: KAI C++
 # pthread-config: use pthread-config program (for GNU Pth library)
 
-case $target_os in
+case $host_os in
 
         freebsd*)
 
@@ -248,7 +248,7 @@ AS_IF([test "x$ax_pthread_clang" = "xyes"],
 # definitions is, on some systems, a strong hint that pthreads support is
 # correctly enabled
 
-case $target_os in
+case $host_os in
         darwin* | hpux* | linux* | osf* | solaris*)
         ax_pthread_check_macro="_REENTRANT"
         ;;
@@ -450,7 +450,7 @@ if test "x$ax_pthread_ok" = "xyes"; then
         AC_CACHE_CHECK([whether more special flags are required for pthreads],
             [ax_cv_PTHREAD_SPECIAL_FLAGS],
             [ax_cv_PTHREAD_SPECIAL_FLAGS=no
-             case $target_os in
+             case $host_os in
              solaris*)
              ax_cv_PTHREAD_SPECIAL_FLAGS="-D_POSIX_PTHREAD_SEMANTICS"
              ;;
@@ -480,7 +480,7 @@ if test "x$ax_pthread_ok" = "xyes"; then
 
         # More AIX lossage: compile with *_r variant
         if test "x$GCC" != "xyes"; then
-            case $target_os in
+            case $host_os in
                 aix*)
                 AS_CASE(["x/$CC"],
                     [x*/c89|x*/c89_128|x*/c99|x*/c99_128|x*/cc|x*/cc128|x*/xlc|x*/xlc_v6|x*/xlc128|x*/xlc128_v6],

m4/require_canonical.m4

@@ -1,3 +0,0 @@
-AC_DEFUN([REQUIRE_CANONICAL], [
-    AC_REQUIRE(AC_CANONICAL_HOST)_LT_SET_OPTION([LT_INIT],[win32-dll])
-])dnl REQUIRE_CANONICAL