Add macros for testing C++0x/11 support in compiler

These files are shamelessly ripped from dune-common/m4 (e28ca3)

m4/cxx0x_compiler.m4

@@ -0,0 +1,60 @@
+# whether compiler accepts -std=c++11 or -std=c++0x
+# can be disabled by --disable-gxx0xcheck
+
+AC_DEFUN([GXX0X],[
+  ac_save_CXX="$CXX"
+  
+  # try flag -std=c++11
+  AC_CACHE_CHECK([whether $CXX accepts -std=c++11], dune_cv_gplusplus_accepts_cplusplus11, [
+    AC_REQUIRE([AC_PROG_CXX])
+    AC_ARG_ENABLE(gxx0xcheck,
+      AC_HELP_STRING([--disable-gxx0xcheck],
+        [try flag -std=c++11 to enable C++11 features [[default=yes]]]),
+        [gxx0xcheck=$enableval],
+        [gxx0xcheck=yes])
+    if test "x$GXX" = xyes && test "x$gxx0xcheck" = xyes; then
+      AC_LANG_PUSH([C++])
+      CXX="$CXX -std=c++11"
+      AC_TRY_COMPILE([
+        #include <iostream>
+        #include <array>
+        ], [],
+        dune_cv_gplusplus_accepts_cplusplus11=yes,
+        dune_cv_gplusplus_accepts_cplusplus11=no)
+      AC_LANG_POP([C++])
+    fi
+  ])
+  if test "x$dune_cv_gplusplus_accepts_cplusplus11" == "xyes" ; then
+    CXX="$ac_save_CXX -std=c++11"
+    CXXCPP="$CXXCPP -std=c++11"
+  else
+    CXX="$ac_save_CXX"
+    
+    # try flag -std=c++0x instead
+    AC_CACHE_CHECK([whether $CXX accepts -std=c++0x], dune_cv_gplusplus_accepts_cplusplus0x, [
+      AC_REQUIRE([AC_PROG_CXX])
+      AC_ARG_ENABLE(gxx0xcheck,
+        AC_HELP_STRING([--disable-gxx0xcheck],
+          [try flag -std=c++0x to enable C++11 features [[default=yes]]]),
+          [gxx0xcheck=$enableval],
+          [gxx0xcheck=yes])
+      if test "x$GXX" = xyes && test "x$gxx0xcheck" = xyes; then
+        AC_LANG_PUSH([C++])
+        CXX="$CXX -std=c++0x"
+        AC_TRY_COMPILE([
+          #include <iostream>
+          #include <array>
+          ], [],
+          dune_cv_gplusplus_accepts_cplusplus0x=yes,
+          dune_cv_gplusplus_accepts_cplusplus0x=no)
+        AC_LANG_POP([C++])
+      fi
+    ])
+    if test "x$dune_cv_gplusplus_accepts_cplusplus0x" == "xyes" ; then
+      CXX="$ac_save_CXX -std=c++0x"
+      CXXCPP="$CXXCPP -std=c++0x"
+    else
+      CXX="$ac_save_CXX"
+    fi
+  fi
+])

m4/cxx0x_nullptr.m4

@@ -0,0 +1,17 @@
+AC_DEFUN([NULLPTR_CHECK],[
+  AC_CACHE_CHECK([whether nullptr is supported], dune_cv_nullptr_support, [
+    AC_REQUIRE([AC_PROG_CXX])
+    AC_REQUIRE([GXX0X])
+    AC_LANG_PUSH([C++])
+    AC_TRY_COMPILE([],[
+      char* ch = nullptr;
+      if(ch!=nullptr) { ; }
+      ], 
+      dune_cv_nullptr_support=yes,
+      dune_cv_nullptr_support=no)
+    AC_LANG_POP
+  ])
+  if test "x$dune_cv_nullptr_support" = xyes; then
+    AC_DEFINE(HAVE_NULLPTR, 1, [Define to 1 if nullptr is supported])
+  fi
+])

m4/cxx0x_static_assert.m4

@@ -0,0 +1,14 @@
+AC_DEFUN([STATIC_ASSERT_CHECK],[
+  AC_CACHE_CHECK([whether static_assert is supported], dune_cv_static_assert_support, [
+    AC_REQUIRE([AC_PROG_CXX])
+    AC_REQUIRE([GXX0X])
+    AC_LANG_PUSH([C++])
+    AC_TRY_COMPILE([],[static_assert(true,"MSG")],
+      dune_cv_static_assert_support=yes,
+      dune_cv_static_assert_support=no)
+    AC_LANG_POP
+  ])
+  if test "x$dune_cv_static_assert_support" = xyes; then
+    AC_DEFINE(HAVE_STATIC_ASSERT, 1, [Define to 1 if static_assert is supported])
+  fi
+])