diff --git a/src/cmd/dist/build.go b/src/cmd/dist/build.go
index d37c3f83efb4d..4687de5d82672 100644
--- a/src/cmd/dist/build.go
+++ b/src/cmd/dist/build.go
@@ -377,6 +377,9 @@ func findgoversion() string {
 					b = "builder " + hostType
 				}
 			}
+			if isGitRepo() {
+				b += "-ts" + chomp(run(goroot, CheckExit, "git", "log", "-n", "1", "--format=format:%h", "HEAD"))
+			}
 			return b
 		}
 	}