Build problems on macOS (possibly related to linking?)

I am having some trouble building Swift on macOS (Catalina 10.15.4). It was working fine before a few days ago, but I checked out the latest sources today and now it seems to fail to build now:

The following build commands failed:
	Ld /Users/suyashsrijan/Documents/swift-src/build/Xcode-RelWithDebInfoAssert/swift-macosx-x86_64/RelWithDebInfo/lib/libswiftDemangle.dylib normal x86_64
(1 failure)
ERROR: command terminated with a non-zero exit status 65, aborting

Building the project using Xcode (11.4.1) gives me the following error:

Invalid linker name in argument '-fuse-ld=lld'

cc @compnerd I reverted your commit from a few days ago and that fixed the problem. Do you know what could be going wrong?

You would need to do a clean build, the previous configuration was incorrect and would implicitly set SWIFT_ENABLE_LLD_LINKER to true instead of false. You could check/change that in CMake cache to avoid the full rebuild as well.