Add more AX_ macros

etc/m4/ax_cxx_static_cast.m4

@@ -0,0 +1,42 @@
+# ===========================================================================
+#    https://www.gnu.org/software/autoconf-archive/ax_cxx_static_cast.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_CXX_STATIC_CAST
+#
+# DESCRIPTION
+#
+#   If the compiler supports static_cast<>, define HAVE_STATIC_CAST.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Todd Veldhuizen
+#   Copyright (c) 2008 Luc Maisonobe <luc@spaceroots.org>
+#
+#   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 8
+
+AU_ALIAS([AC_CXX_STATIC_CAST], [AX_CXX_STATIC_CAST])
+AC_DEFUN([AX_CXX_STATIC_CAST],
+[AC_CACHE_CHECK(whether the compiler supports static_cast<>,
+ax_cv_cxx_static_cast,
+[AC_LANG_PUSH([C++])
+ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <typeinfo>
+class Base { public : Base () {} virtual void f () = 0; };
+class Derived : public Base { public : Derived () {} virtual void f () {} };
+int g (Derived&) { return 0; }]], [[
+Derived d; Base& b = d; Derived& s = static_cast<Derived&> (b); return g (s);]])],
+ [ax_cv_cxx_static_cast=yes], [ax_cv_cxx_static_cast=no])
+ AC_LANG_POP([C++])
+])
+if test "$ax_cv_cxx_static_cast" = yes; then
+  AC_DEFINE(HAVE_STATIC_CAST,,
+            [define if the compiler supports static_cast<>])
+fi
+])