Merge pull request #14 from rleigh-codelibre/XERCESC-2141_build_suppo…

…rt_for_c++11_onwards

XERCESC-2141: Enable C++17, C++14 or C++11 when available

CMakeLists.txt

@@ -32,9 +32,9 @@ if (POLICY CMP0067)
   cmake_policy(SET CMP0067 NEW)
 endif(POLICY CMP0067)
 
-# Try C++14, then fall back to C++11 and C++98.  Used for feature tests
+# Try C++17, then fall back to C++14, C++11 then C++98.  Used for feature tests
 # for optional features.
-set(CMAKE_CXX_STANDARD 14)
+set(CMAKE_CXX_STANDARD 17)
 
 # Use folders (for IDE project grouping)
 set_property(GLOBAL PROPERTY USE_FOLDERS ON)

configure.ac

@@ -79,6 +79,15 @@ AM_SILENT_RULES([yes])
 AM_INIT_AUTOMAKE([foreign subdir-objects dist-bzip2 tar-ustar])
 AM_MAINTAINER_MODE
 
+# Checks for C++ standard version
+AX_CXX_COMPILE_STDCXX([17], [ext], [optional])
+if test "$HAVE_CXX17" = "0"; then
+  AX_CXX_COMPILE_STDCXX([14], [ext], [optional])
+  if test "$HAVE_CXX14" = "0"; then
+    AX_CXX_COMPILE_STDCXX([11], [ext], [optional])
+  fi
+fi
+
 # Check if rpath is disabled
 AC_MSG_CHECKING(whether to use rpath)
 AC_ARG_ENABLE(rpath,