diff --git a/go/tools/builders/cgo2.go b/go/tools/builders/cgo2.go
index d6cd6a2d0e..4320030339 100644
--- a/go/tools/builders/cgo2.go
+++ b/go/tools/builders/cgo2.go
@@ -210,6 +210,7 @@ func cgo2(goenv *env, goSrcs, cgoSrcs, cSrcs, cxxSrcs, objcSrcs, objcxxSrcs, sSr
 			// and MSVC isn't supported at all.
 			return "", nil, nil, err
 		case "darwin":
+			fallthrough
 		case "ios":
 			allowUnresolvedSymbolsLdFlags = []string{"-Wl,-undefined,dynamic_lookup"}
 		default: