cmd/dist: build cmd/compile/internal/syntax

Change-Id: Ie6dd2318e031be445c0b1ae65d4c78723d5a1167
diff --git a/src/cmd/dist/buildtool.go b/src/cmd/dist/buildtool.go
index a535316..ca1b341 100644
--- a/src/cmd/dist/buildtool.go
+++ b/src/cmd/dist/buildtool.go
@@ -36,9 +36,10 @@
 	"compile/internal/gc",
 	"compile/internal/mips64",
 	"compile/internal/ppc64",
-	"compile/internal/ssa",
-	"compile/internal/x86",
 	"compile/internal/s390x",
+	"compile/internal/ssa",
+	"compile/internal/syntax",
+	"compile/internal/x86",
 	"internal/bio",
 	"internal/gcprog",
 	"internal/obj",