ld: unexpected token: !tapi-tbd-v3 file '/System/Library/Frameworks//CoreServices.framework/CoreServices.tbd' for architecture x86_64

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

Just for the record: After upgrading to MacOS 10.13 (High Sierra), I needed to 
re-install the Developer Command Line Tools (xcode-select --install) in order 
to be able to bootstrap, but for several packages, I got
	ld: unexpected token: !tapi-tbd-v3 file '/System/Library/Frameworks//CoreServices.framework/CoreServices.tbd' for architecture x86_64

The reason was xcode-select -p giving
	/Applications/Xcode/Contents/Developer/CommandLineTools
which didn't exist.
The cure was
	xcode-select -s /Library/Developer/CommandLineTools
which did exist.