Update autotools m4

aclocal/ax_boost_base.m4

@@ -33,7 +33,7 @@
 #   and this notice are preserved. This file is offered as-is, without any
 #   warranty.
 
-#serial 48
+#serial 49
 
 # example boost program (need to pass version)
 m4_define([_AX_BOOST_BASE_PROGRAM],
@@ -114,7 +114,7 @@ AC_DEFUN([_AX_BOOST_BASE_RUNDETECT],[
     AS_CASE([${host_cpu}],
       [x86_64],[libsubdirs="lib64 libx32 lib lib64"],
       [mips*64*],[libsubdirs="lib64 lib32 lib lib64"],
-      [ppc64|powerpc64|s390x|sparc64|aarch64|ppc64le|powerpc64le|riscv64],[libsubdirs="lib64 lib lib64"],
+      [ppc64|powerpc64|s390x|sparc64|aarch64|ppc64le|powerpc64le|riscv64|e2k],[libsubdirs="lib64 lib lib64"],
       [libsubdirs="lib"]
     )
 

aclocal/ax_boost_program_options.m4

@@ -29,7 +29,7 @@
 #   and this notice are preserved. This file is offered as-is, without any
 #   warranty.
 
-#serial 25
+#serial 26
 
 AC_DEFUN([AX_BOOST_PROGRAM_OPTIONS],
 [
@@ -96,7 +96,7 @@ AC_DEFUN([AX_BOOST_PROGRAM_OPTIONS],
                   done
                 fi
             if test "x$ax_lib" = "x"; then
-                AC_MSG_ERROR(Could not find a version of the library!)
+                AC_MSG_ERROR(Could not find a version of the Boost::Program_Options library!)
             fi
 				if test "x$link_program_options" != "xyes"; then
 					AC_MSG_ERROR([Could not link against [$ax_lib] !])

aclocal/ax_cxx_compile_stdcxx.m4

@@ -10,13 +10,13 @@
 #
 #   Check for baseline language coverage in the compiler for the specified
 #   version of the C++ standard.  If necessary, add switches to CXX and
-#   CXXCPP to enable support.  VERSION may be '11' (for the C++11 standard)
-#   or '14' (for the C++14 standard).
+#   CXXCPP to enable support.  VERSION may be '11', '14', '17', or '20' for
+#   the respective C++ standard version.
 #
 #   The second argument, if specified, indicates whether you insist on an
 #   extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g.
 #   -std=c++11).  If neither is specified, you get whatever works, with
-#   preference for an extended mode.
+#   preference for no added switch, and then for an extended mode.
 #
 #   The third argument, if specified 'mandatory' or if left unspecified,
 #   indicates that baseline support for the specified C++ standard is
@@ -34,13 +34,16 @@
 #   Copyright (c) 2015 Paul Norman <penorman@mac.com>
 #   Copyright (c) 2015 Moritz Klammler <moritz@klammler.eu>
 #   Copyright (c) 2016, 2018 Krzesimir Nowak <qdlacz@gmail.com>
+#   Copyright (c) 2019 Enji Cooper <yaneurabeya@gmail.com>
+#   Copyright (c) 2020 Jason Merrill <jason@redhat.com>
+#   Copyright (c) 2021 Jörn Heusipp <osmanx@problemloesungsmaschine.de>
 #
 #   Copying and distribution of this file, with or without modification, are
 #   permitted in any medium without royalty provided the copyright notice
 #   and this notice are preserved.  This file is offered as-is, without any
 #   warranty.
 
-#serial 10
+#serial 14
 
 dnl  This macro is based on the code from the AX_CXX_COMPILE_STDCXX_11 macro
 dnl  (serial version number 13).
@@ -49,6 +52,7 @@ AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl
   m4_if([$1], [11], [ax_cxx_compile_alternatives="11 0x"],
         [$1], [14], [ax_cxx_compile_alternatives="14 1y"],
         [$1], [17], [ax_cxx_compile_alternatives="17 1z"],
+        [$1], [20], [ax_cxx_compile_alternatives="20"],
         [m4_fatal([invalid first argument `$1' to AX_CXX_COMPILE_STDCXX])])dnl
   m4_if([$2], [], [],
         [$2], [ext], [],
@@ -61,6 +65,16 @@ AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl
   AC_LANG_PUSH([C++])dnl
   ac_success=no
 
+  m4_if([$2], [], [dnl
+    AC_CACHE_CHECK(whether $CXX supports C++$1 features by default,
+		   ax_cv_cxx_compile_cxx$1,
+      [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
+        [ax_cv_cxx_compile_cxx$1=yes],
+        [ax_cv_cxx_compile_cxx$1=no])])
+    if test x$ax_cv_cxx_compile_cxx$1 = xyes; then
+      ac_success=yes
+    fi])
+
   m4_if([$2], [noext], [], [dnl
   if test x$ac_success = xno; then
     for alternative in ${ax_cxx_compile_alternatives}; do
@@ -139,20 +153,31 @@ m4_define([_AX_CXX_COMPILE_STDCXX_testbody_11],
   _AX_CXX_COMPILE_STDCXX_testbody_new_in_11
 )
 
-
 dnl  Test body for checking C++14 support
 
 m4_define([_AX_CXX_COMPILE_STDCXX_testbody_14],
   _AX_CXX_COMPILE_STDCXX_testbody_new_in_11
   _AX_CXX_COMPILE_STDCXX_testbody_new_in_14
 )
 
+dnl  Test body for checking C++17 support
+
 m4_define([_AX_CXX_COMPILE_STDCXX_testbody_17],
   _AX_CXX_COMPILE_STDCXX_testbody_new_in_11
   _AX_CXX_COMPILE_STDCXX_testbody_new_in_14
   _AX_CXX_COMPILE_STDCXX_testbody_new_in_17
 )
 
+dnl  Test body for checking C++20 support
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_20],
+  _AX_CXX_COMPILE_STDCXX_testbody_new_in_11
+  _AX_CXX_COMPILE_STDCXX_testbody_new_in_14
+  _AX_CXX_COMPILE_STDCXX_testbody_new_in_17
+  _AX_CXX_COMPILE_STDCXX_testbody_new_in_20
+)
+
+
 dnl  Tests for new features in C++11
 
 m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_11], [[
@@ -189,11 +214,13 @@ namespace cxx11
 
     struct Base
     {
+      virtual ~Base() {}
       virtual void f() {}
     };
 
     struct Derived : public Base
     {
+      virtual ~Derived() override {}
       virtual void f() override {}
     };
 
@@ -946,3 +973,33 @@ namespace cxx17
 #endif  // __cplusplus < 201703L
 
 ]])
+
+
+dnl  Tests for new features in C++20
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_20], [[
+
+#ifndef __cplusplus
+
+#error "This is not a C++ compiler"
+
+#elif __cplusplus < 202002L
+
+#error "This is not a C++20 compiler"
+
+#else
+
+#include <version>
+
+namespace cxx20
+{
+
+// As C++20 supports feature test macros in the standard, there is no
+// immediate need to actually test for feature availability on the
+// Autoconf side.
+
+}  // namespace cxx20
+
+#endif  // __cplusplus < 202002L
+
+]])