Ticket #41460: patch-configure.ac.diff

configure.ac

@@ -23 +23 @@
 AC_SUBST([ADDED_CXXFLAGS])
 
 # Extended initializer lists were added in 4.4.
+# Clang fraudulently identifies itself as an old GCC.
 AC_MSG_CHECKING([if using a version of GCC older than 4.4])
 AC_PREPROC_IFELSE(
   [AC_LANG_SOURCE([[
+#ifndef __clang__
 #ifdef __GNUC__
 #if (__GNUC__ * 100 + __GNUC_MINOR__) < 404
 #FAIL
 #endif
 #endif
+#endif
   ]])],
   [
     AC_MSG_RESULT(no)
@@ -107 +110 @@
   [
     AC_MSG_RESULT(no)
     AC_MSG_CHECKING([if it helps to add -std=gnu++0x to CXXFLAGS])
-    CXXFLAGS="-std=gnu++0x ${CXXFLAGS}"
+    CXXFLAGS="-std=gnu++0x ${SAVED_CXXFLAGS}"
     AC_COMPILE_IFELSE(
       [AC_LANG_PROGRAM([[#include <vector>]],
                        [[std::vector<int> test = {1}]])],
@@ -117 +120 @@
       ],
       [
         AC_MSG_RESULT(no)
-        AC_DEFINE(NO_INITIALIZER_LISTS)
-        SKIP_COMPLICATED=1
+        # Clang needs -std=c++11 instead
+        AC_MSG_CHECKING([if it helps to add -std=c++11 to CXXFLAGS])
+        CXXFLAGS="-std=c++11 ${SAVED_CXXFLAGS}"
+        AC_COMPILE_IFELSE(
+          [AC_LANG_PROGRAM([[#include <vector>]],
+                           [[std::vector<int> test = {1}]])],
+          [
+            AC_MSG_RESULT(yes)
+            ADDED_CXXFLAGS="${ADDED_CXXFLAGS} -std=c++11"
+          ],
+          [
+            AC_MSG_RESULT(no)
+            AC_DEFINE(NO_INITIALIZER_LISTS)
+            SKIP_COMPLICATED=1
+          ]
+        )
       ]
     )
   ]