Conflicts:
 * build.zig
 * src/Compilation.zig
 * src/codegen/spirv/spec.zig
 * src/link/SpirV.zig
 * test/stage2/darwin.zig
   - this one might be problematic; start.zig looks for `main` in the
     root source file, not `_main`. Not sure why there is an underscore
     there in master branch.