allow c++14

scripts/ax_cxx_compile_stdcxx_11.m4

@@ -4,12 +4,16 @@
 #
 # SYNOPSIS
 #
+#   AX_REQUIRE_STDCXX_11
+#   AX_REQUIRE_STDCXX_14
 #   AX_CXX_COMPILE_STDCXX_11([ext|noext],[mandatory|optional])
+#   AX_CXX_COMPILE_STDCXX_14([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.
+#   or C++14 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.
@@ -131,3 +135,95 @@ AC_DEFUN([AX_CXX_COMPILE_STDCXX_11], [dnl
     AC_SUBST(HAVE_CXX11)
   fi
 ])
+
+AC_DEFUN([AX_CXX_COMPILE_STDCXX_14], [dnl
+  m4_if([$1], [], [],
+        [$1], [ext], [],
+        [$1], [noext], [],
+        [m4_fatal([invalid argument `$1' to AX_CXX_COMPILE_STDCXX_14])])dnl
+  m4_if([$2], [], [ax_cxx_compile_cxx14_required=true],
+        [$2], [mandatory], [ax_cxx_compile_cxx14_required=true],
+        [$2], [optional], [ax_cxx_compile_cxx14_required=false],
+        [m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX_14])])dnl
+  AC_LANG_PUSH([C++])dnl
+  ac_success=no
+  AC_CACHE_CHECK(whether $CXX supports C++14 features by default,
+  ax_cv_cxx_compile_cxx14,
+  [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])],
+    [ax_cv_cxx_compile_cxx14=yes],
+    [ax_cv_cxx_compile_cxx14=no])])
+  if test x$ax_cv_cxx_compile_cxx14 = xyes; then
+    ac_success=yes
+  fi
+
+  m4_if([$1], [noext], [], [dnl
+  if test x$ac_success = xno; then
+    for switch in -std=gnu++14 -std=gnu++0y; do
+      cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx14_$switch])
+      AC_CACHE_CHECK(whether $CXX supports C++14 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])
+
+  m4_if([$1], [ext], [], [dnl
+  if test x$ac_success = xno; then
+    for switch in -std=c++14 -std=c++0y; do
+      cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx14_$switch])
+      AC_CACHE_CHECK(whether $CXX supports C++14 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_cxx14_required = xtrue; then
+    if test x$ac_success = xno; then
+      AC_MSG_ERROR([*** A compiler with support for C++14 language features is required.])
+    fi
+  else
+    HAVE_CXX11=${HAVE_CXX14}
+    if test x$ac_success = xno; then
+      HAVE_CXX14=0
+      AC_MSG_NOTICE([No compiler with C++14 support was found])
+      AX_CXX_COMPILE_STDCXX_11([$1], [optional])
+    else
+      HAVE_CXX14=1
+      AC_DEFINE(HAVE_CXX14,1,
+                [define if the compiler supports basic C++14 syntax])
+    fi
+    AC_SUBST(HAVE_CXX11)
+    AC_SUBST(HAVE_CXX14)
+  fi
+])
+
+AC_DEFUN([AX_REQUIRE_STDCXX_11], [
+  if test x${HAVE_CXX11} != x1; then
+    AC_MSG_ERROR([*** A compiler with support for C++11 language features is required.])
+  fi
+])
+
+AC_DEFUN([AX_REQUIRE_STDCXX_14], [
+  if test x${HAVE_CXX14} != x1; then
+    AC_MSG_ERROR([*** A compiler with support for C++14 language features is required.])
+  fi
+])

scripts/ax_init_standard_project.m4

@@ -129,7 +129,7 @@ AC_DEFUN([AX_SUBST], [
 # m4_define(x_minor, MINOR_NUMBER) # project's minor version
 # m4_include(ax_init_standard_project.m4)
 # AC_INIT(x_package_name, x_version, x_bugreport, x_package_name)
-# AM_INIT_AUTOMAKE([1.9 tar-pax])
+# AM_INIT_AUTOMAKE([1.9 tar-pax parallel-tests color-tests])
 # AX_INIT_STANDARD_PROJECT
 #
 # you change nothing but: YOUR_PACKAGE_NAME, MAJOR_NUMBER, MINOR_NUMBER
@@ -273,7 +273,7 @@ EOF
 AC_DEFUN([AX_USE_CXX], [
   m4_include(ax_cxx_compile_stdcxx_11.m4)
   AC_LANG(C++)
-  AX_CXX_COMPILE_STDCXX_11(noext, optional)
+  AX_CXX_COMPILE_STDCXX_14(noext, optional)
   AC_PROG_CXX
   AC_PROG_CPP