It's useful to capture the platform and platform version with the image map.
Also, display both the platform and architecture information when generating
a crash log.
rdar://124913332
Move the backtracing code into a new Runtime module. This means renaming
the Swift Runtime's CMake target because otherwise there will be a name
clash.
rdar://124913332
Fixed the colours so that they work with all of the default Terminal
presets. Also changed things so that when colour is off, we only use
ASCII characters in our source code displays.
rdar://105452194
This is Swift's external backtracer. It's written in Swift, and it's
responsible for generating nice backtraces when Swift programs crash.
It makes use of the new `_Backtracing` library, which is also (mostly,
aside from some assembly language) implemented in Swift.
rdar://103442000
