[regression vs native] "search path not found" when executable path contains whitespaces

[MahdiBM]

I've just started to try out swift-build, and I'm seeing these warnings:

/Applications/Xcode 26 beta 4.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift build --build-tests --disable-xctest --build-system=swiftbuild

Building for debugging...
                                                                                                                                                    
83% [======================================================================================================================================================================================================================================------------------------------------------------]
warning: Search path '/Applications/Xcode' not found
warning: Search path '26' not found
warning: Search path 'beta' not found

• This is with using the official VSCode extension.
• The extension is the place that triggers the build command.
• These don't appear to be show-stoppers.
• Only happens when I change a file and rebuild. For a build with no changes, these warnings don't happen.
• The native build system works fine.

I'll just rename my Xcode if I have to for now, but thought it's worth reporting.

[MahdiBM]

Later on I started seeing some other errors which can be showstoppers this time.
I think it was about clang, something like:

/Applications/Xcode 26 beta 4.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang

I think when swift-build was trying to trigger clang?

I think swift-build currently is just not well-prepared for CLI arguments with spaces in them.

[owenv]

It's less of a problem with the build system itself and more of a problem with how we're invoking it from SwiftPM currently. #768 addresses a lot of the Windows and Linux issues but this is probably a separate issue