--- src/cmd/dist/util.go.
+++ src/cmd/dist/util.go
@@ -404,7 +404,7 @@
 	switch gohostos {
 	case "darwin":
 		// Even on 64-bit platform, darwin uname -m prints i386.
-		if strings.Contains(run("", CheckExit, "sysctl", "machdep.cpu.extfeatures"), "EM64T") {
+		if strings.Contains(run("", CheckExit, "/usr/sbin/sysctl", "machdep.cpu.extfeatures"), "EM64T") {
 			gohostarch = "amd64"
 		}
 	case "solaris":