Unify macros for checking C++11/14/... compiler support.

* m4/ax_cxx_compile_stdcxx.m4: New macro file added.

(AX_CXX_COMPILE_STDCXX): New macro added.  The code is based on
the former (serial version number 13) `AX_CXX_COMPILE_STDCXX_11`
macro, generalized to check for arbitrary versions of the standard
selected via an additional argument.

(_AX_CXX_COMPILE_STDCXX_testbody_11): New internal macro added.
Defined in terms of `_AX_CXX_COMPILE_STDCXX_testbody_new_in_11`.

(_AX_CXX_COMPILE_STDCXX_testbody_14): New internal macro added.
Defined in terms of `_AX_CXX_COMPILE_STDCXX_testbody_new_in_11`
and `_AX_CXX_COMPILE_STDCXX_testbody_new_in_14`.

(_AX_CXX_COMPILE_STDCXX_testbody_new_in_11): New internal macro
added.  Test code to check for features added in C++14.  It is
based on the code previously found in the
`_AX_CXX_COMPILE_STDCXX_11_testbody` macro, defined in
`m4/ax_cxx_compile_stdcxx_11.m4` but heavily refactored and
extended with additional checks.

(_AX_CXX_COMPILE_STDCXX_testbody_new_in_14): New internal macro
added.  Test code to check for features added in C++14.

* m4/ax_cxx_compile_stdcxx_11.m4:

(AX_CXX_COMPILE_STDCXX_11): Make this macro an alias for the new
`AX_CXX_COMPILE_STDCXX` macro with the version set to C++11.

(_AX_CXX_COMPILE_STDCXX_11_testbody): Internal macro deleted.

* m4/ax_cxx_compile_stdcxx_14.m4: New macro file added.

(AX_CXX_COMPILE_STDCXX_14): New macro added.  This macro is an
alias for the new `AX_CXX_COMPILE_STDCXX` macro with the version
set to C++14.

* m4/ax_cxx_compile_stdcxx_0x.m4 (AX_CXX_COMPILE_STDCXX_0X): Mark
macro as obsolete.  The macro `AX_CXX_COMPILE_STDCXX_11` should be
used instead.  I couldn't test this macro on my system because it
uses a lot of obsolete macros my Autoconf complains about and
errors out.

1 files changed, 11 insertions, 144 deletions

diff --git a/m4/ax_cxx_compile_stdcxx_11.m4 b/m4/ax_cxx_compile_stdcxx_11.m4
index 516da37..09db383 100644
--- a/m4/ax_cxx_compile_stdcxx_11.m4
+++ b/m4/ax_cxx_compile_stdcxx_11.m4
@@ -4,23 +4,19 @@
 #
 # SYNOPSIS
 #
-#   AX_CXX_COMPILE_STDCXX_11([ext|noext],[mandatory|optional])
+#   AX_CXX_COMPILE_STDCXX_11([ext|noext], [mandatory|optional])
 #
 # DESCRIPTION
 #
 #   Check for baseline language coverage in the compiler for the C++11
 #   standard; if necessary, add switches to CXXFLAGS to enable support.
 #
-#   The first 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.
-#
-#   The second argument, if specified 'mandatory' or if left unspecified,
-#   indicates that baseline C++11 support is required and that the macro
-#   should error out if no mode with that support is found.  If specified
-#   'optional', then configuration proceeds regardless, after defining
-#   HAVE_CXX11 if and only if a supporting mode is found.
+#   This macro is a convenience alias for calling the AX_CXX_COMPILE_STDCXX
+#   macro with the version set to C++11.  The two optional arguments are
+#   forwarded literally as the second and third argument respectively.
+#   Please see the documentation for the AX_CXX_COMPILE_STDCXX macro for
+#   more information.  If you want to use this macro, you also need to
+#   download the ax_cxx_compile_stdcxx.m4 file.
 #
 # LICENSE
 #
@@ -29,144 +25,15 @@
 #   Copyright (c) 2013 Roy Stogner <roystgnr@ices.utexas.edu>
 #   Copyright (c) 2014, 2015 Google Inc.; contributed by Alexey Sokolov <sokolov@google.com>
 #   Copyright (c) 2015 Paul Norman <penorman@mac.com>
+#   Copyright (c) 2015 Moritz Klammler <moritz@klammler.eu>
 #
 #   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 13
-
-m4_define([_AX_CXX_COMPILE_STDCXX_11_testbody], [[
-  template <typename T>
-    struct check
-    {
-      static_assert(sizeof(int) <= sizeof(T), "not big enough");
-    };
-
-    struct Base {
-    virtual void f() {}
-    };
-    struct Child : public Base {
-    virtual void f() override {}
-    };
-
-    typedef check<check<bool>> right_angle_brackets;
-
-    int a;
-    decltype(a) b;
-
-    typedef check<int> check_type;
-    check_type c;
-    check_type&& cr = static_cast<check_type&&>(c);
-
-    auto d = a;
-    auto l = [](){};
-    // Prevent Clang error: unused variable 'l' [-Werror,-Wunused-variable]
-    struct use_l { use_l() { l(); } };
-
-    // http://stackoverflow.com/questions/13728184/template-aliases-and-sfinae
-    // Clang 3.1 fails with headers of libstd++ 4.8.3 when using std::function because of this
-    namespace test_template_alias_sfinae {
-        struct foo {};
-
-        template<typename T>
-        using member = typename T::member_type;
-
-        template<typename T>
-        void func(...) {}
-
-        template<typename T>
-        void func(member<T>*) {}
-
-        void test();
-
-        void test() {
-            func<foo>(0);
-        }
-    }
-
-    // Check for C++11 attribute support
-    void noret [[noreturn]] () { throw 0; }
-]])
-
-AC_DEFUN([AX_CXX_COMPILE_STDCXX_11], [dnl
-  m4_if([$1], [], [],
-        [$1], [ext], [],
-        [$1], [noext], [],
-        [m4_fatal([invalid argument `$1' to AX_CXX_COMPILE_STDCXX_11])])dnl
-  m4_if([$2], [], [ax_cxx_compile_cxx11_required=true],
-        [$2], [mandatory], [ax_cxx_compile_cxx11_required=true],
-        [$2], [optional], [ax_cxx_compile_cxx11_required=false],
-        [m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX_11])])
-  AC_LANG_PUSH([C++])dnl
-  ac_success=no
-  AC_CACHE_CHECK(whether $CXX supports C++11 features by default,
-  ax_cv_cxx_compile_cxx11,
-  [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])],
-    [ax_cv_cxx_compile_cxx11=yes],
-    [ax_cv_cxx_compile_cxx11=no])])
-  if test x$ax_cv_cxx_compile_cxx11 = xyes; then
-    ac_success=yes
-  fi
-
-  m4_if([$1], [noext], [], [dnl
-  if test x$ac_success = xno; then
-    for switch in -std=gnu++11 -std=gnu++0x; do
-      cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx11_$switch])
-      AC_CACHE_CHECK(whether $CXX supports C++11 features with $switch,
-                     $cachevar,
-        [ac_save_CXXFLAGS="$CXXFLAGS"
-         CXXFLAGS="$CXXFLAGS $switch"
-         AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])],
-          [eval $cachevar=yes],
-          [eval $cachevar=no])
-         CXXFLAGS="$ac_save_CXXFLAGS"])
-      if eval test x\$$cachevar = xyes; then
-        CXXFLAGS="$CXXFLAGS $switch"
-        ac_success=yes
-        break
-      fi
-    done
-  fi])
+#serial 14
 
-  m4_if([$1], [ext], [], [dnl
-  if test x$ac_success = xno; then
-    dnl HP's aCC needs +std=c++11 according to:
-    dnl http://h21007.www2.hp.com/portal/download/files/unprot/aCxx/PDF_Release_Notes/769149-001.pdf
-    dnl Cray's crayCC needs "-h std=c++11"
-    for switch in -std=c++11 -std=c++0x +std=c++11 "-h std=c++11"; do
-      cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx11_$switch])
-      AC_CACHE_CHECK(whether $CXX supports C++11 features with $switch,
-                     $cachevar,
-        [ac_save_CXXFLAGS="$CXXFLAGS"
-         CXXFLAGS="$CXXFLAGS $switch"
-         AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])],
-          [eval $cachevar=yes],
-          [eval $cachevar=no])
-         CXXFLAGS="$ac_save_CXXFLAGS"])
-      if eval test x\$$cachevar = xyes; then
-        CXXFLAGS="$CXXFLAGS $switch"
-        ac_success=yes
-        break
-      fi
-    done
-  fi])
-  AC_LANG_POP([C++])
-  if test x$ax_cxx_compile_cxx11_required = xtrue; then
-    if test x$ac_success = xno; then
-      AC_MSG_ERROR([*** A compiler with support for C++11 language features is required.])
-    fi
-  else
-    if test x$ac_success = xno; then
-      HAVE_CXX11=0
-      AC_MSG_NOTICE([No compiler with C++11 support was found])
-    else
-      HAVE_CXX11=1
-      AC_DEFINE(HAVE_CXX11,1,
-                [define if the compiler supports basic C++11 syntax])
-    fi
+include([ax_cxx_compile_stdcxx.m4])
 
-    AC_SUBST(HAVE_CXX11)
-  fi
-])
+AC_DEFUN([AX_CXX_COMPILE_STDCXX_11], [AX_CXX_COMPILE_STDCXX([11], [$1], [$2])])