Xcode 6 beta 5: compile error "Using undeclared identifier" char32_t "when changing deployment target to 7.0

In my current project, I have used OC and Swift. Mixed code works fine in Xcode 6 beta. Currently, when I update Xcode 6 beta to beta 5. Then I encountered a lot of compilation errors, most of which are mainly caused by new features of the Swift language. I have fixed all syntax related errors, remaining one compilation error, which is:

"Swift is not available on iOS before 7.0, set IPHONEOS_DEPLOYMENT_TARGET to 7.0 or newer (currently" 4.3 ")"

When I changed the deployment target to 7.0 and compiled the project, new compilation errors occurred:

"Using the undeclared identifier 'char32_t'"

This compilation error appears in the file / Applications / Xcode6-Beta5.app / Contents / Developer / Toolchains / XcodeDefault.xctoolchain / usr / include / C ++ / v1.