Work around GCC linking errors within libc++abi due to missing new/delete definitions

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@296822 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 03e0f68..45ef0c0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -159,7 +159,12 @@
 
 set(ENABLE_NEW_DELETE_DEFAULT ON)
 if (LIBCXXABI_ENABLE_NEW_DELETE_DEFINITIONS)
-  set(ENABLE_NEW_DELETE_DEFAULT OFF)
+# FIXME: This option should default to off. Unfortunatly GCC 4.9 fails to link
+# programs to due undefined references to new/delete in libc++abi so to work
+# around this libc++abi currently defaults LIBCXXABI_ENABLE_NEW_DELETE_DEFINITIONS
+# to ON. Once the GCC bug has been worked around this option should be changed
+# back to OFF.
+  set(ENABLE_NEW_DELETE_DEFAULT ON)
 endif()
 
 option(LIBCXX_ENABLE_NEW_DELETE_DEFINITIONS