Merge pull request swiftlang#33607 from davidungar/readme-addition

Add warning about spaces in the Xcode path.

Author: David Ungar

README.md

@@ -104,6 +104,14 @@ The required version of Xcode changes frequently, and is often a beta release.
 Check this document or the host information on <https://ci.swift.org> for the
 current required version.
 
+Swift's build tooling is meant to support spaces in the paths passed to them,
+but using spaces sometimes tickles bugs in Swift's build scripts or the tools
+they rely on. For example, [SR-13441](https://bugs.swift.org/browse/SR-13441)
+is caused by a space in the Xcode path used on macOS. If you see Swift's build
+tooling misbehave due to a space in a path, please
+[report the bug on the Swift bug tracker](https://swift.org/contributing/#reporting-bugs)
+and then change the path to work around it.
+
 You will also need [CMake](https://cmake.org) and [Ninja](https://ninja-build.org),
 which can be installed via a package manager: