Currently trying the latest distribution of the tools from Xcode 11.4b. It appears SPM 5.2 does not follow the symlinks for directories that contain source files (that it did in previous releases). We could fix it by explicitly specifying the
.target.path property (though such custom paths won't show in Xcode…).
I'd be interested to know if it is made on purpose (security, etc) or if this is a temporary bug in this version of the tooling.