swift

649743a3 - [Build][Backtracer] Make the CMakeLists.txt fatal error on x86.

[Build][Backtracer] Make the CMakeLists.txt fatal error on x86. On compnerd's suggestion, make CMakeLists.txt for `swift-backtrace` fatal error on 32-bit x86, since it won't work there until we fix Swift to respect `stdcall`. rdar://170769502