The project does load in Xcode 13.2. To successfully build, one has to change the working directory for the build step to point to where the source code is (click on Sil.app icon in the left pane of Xcode; then, in the center pane, select the Sil from TARGETS and then select the Info tab to set that working directory).
For simply building the executable, the instructions in README.md (use Makefile.cocoa directly and skip Xcode) would be what I would use.
The project does load in Xcode 13.2. To successfully build, one has to change the working directory for the build step to point to where the source code is (click on Sil.app icon in the left pane of Xcode; then, in the center pane, select the Sil from TARGETS and then select the Info tab to set that working directory).
For simply building the executable, the instructions in README.md (use Makefile.cocoa directly and skip Xcode) would be what I would use.