diff --git a/src/cmd/gc/popt.h b/src/cmd/gc/popt.h
index 0a30e81f55..4e89dbd678 100644
--- a/src/cmd/gc/popt.h
+++ b/src/cmd/gc/popt.h
@@ -118,7 +118,8 @@ EXTERN	Bits	ovar;
 EXTERN	int	change;
 EXTERN	int32	maxnr;
 
-EXTERN	struct
+typedef struct OptStats OptStats;
+struct OptStats
 {
 	int32	ncvtreg;
 	int32	nspill;
@@ -126,7 +127,9 @@ EXTERN	struct
 	int32	ndelmov;
 	int32	nvar;
 	int32	naddr;
-} ostats;
+};
+
+EXTERN	OptStats ostats;
 
 /*
  * reg.c
diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index 0e69f88b66..50dae8ca68 100644
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -634,7 +634,7 @@ walkexpr(Node **np, NodeList **init)
 
 			// Append captured variables to argument list.
 			n->list = concat(n->list, n->left->enter);
-			n->left->enter = NULL;
+			n->left->enter = nil;
 			// Replace OCLOSURE with ONAME/PFUNC.
 			n->left = n->left->closure->nname;
 			// Update type of OCALLFUNC node.
diff --git a/src/cmd/ld/dwarf.c b/src/cmd/ld/dwarf.c
index 53f0194b31..bd94d11d9c 100644
--- a/src/cmd/ld/dwarf.c
+++ b/src/cmd/ld/dwarf.c
@@ -104,7 +104,7 @@ uleb128enc(uvlong v, char* dst)
 		len++;
 	} while (c & 0x80);
 	return len;
-};
+}
 
 static int
 sleb128enc(vlong v, char *dst)
diff --git a/src/runtime/stack.h b/src/runtime/stack.h
index 88c7e02f40..b64123e80f 100644
--- a/src/runtime/stack.h
+++ b/src/runtime/stack.h
@@ -22,6 +22,10 @@ enum {
 #define STACKSYSTEM 0
 #endif
 
+	/*c2go
+	STACKSYSTEM = 0,
+	*/
+
 	StackSystem = STACKSYSTEM,
 
 	StackBig = 4096,