Macros can't be expressions, so make a function

Macros can't be expressions, that is a GNU extension (I didn't know
that).  This commit converts the macro to a function so that everything
will compile correctly on non-GNU compatible compilers.

node.h

@@ -281,15 +281,11 @@ typedef struct RNode {
 #define nd_apinfo u3.apinfo
 
 #define NEW_NODE(t,a0,a1,a2,loc) rb_node_newnode((t),(VALUE)(a0),(VALUE)(a1),(VALUE)(a2),loc)
+#define NEW_NODE_WITH_LOCALS(t,a1,a2,loc) node_newnode_with_locals(p, (t),(VALUE)(a1),(VALUE)(a2),loc)
 
 #define NEW_DEFN(i,a,d,loc) NEW_NODE(NODE_DEFN,0,i,NEW_SCOPE(a,d,loc),loc)
 #define NEW_DEFS(r,i,a,d,loc) NEW_NODE(NODE_DEFS,r,i,NEW_SCOPE(a,d,loc),loc)
-#define NEW_SCOPE(a,b,loc) ({ \
-    VALUE tbl = 0; \
-    NODE * _n = NEW_NODE(NODE_SCOPE,local_tbl(p, &tbl),b,a,loc); \
-    tbl && RB_OBJ_WRITTEN(p->ast, Qnil, tbl); \
-    _n; \
-})
+#define NEW_SCOPE(a,b,loc) NEW_NODE_WITH_LOCALS(NODE_SCOPE,b,a,loc)
 #define NEW_BLOCK(a,loc) NEW_NODE(NODE_BLOCK,a,0,0,loc)
 #define NEW_IF(c,t,e,loc) NEW_NODE(NODE_IF,c,t,e,loc)
 #define NEW_UNLESS(c,t,e,loc) NEW_NODE(NODE_UNLESS,c,t,e,loc)

parse.y

@@ -347,6 +347,8 @@ add_mark_object(struct parser_params *p, VALUE obj)
     }
     return obj;
 }
+#else
+static NODE* node_newnode_with_locals(struct parser_params *, enum node_type, VALUE, VALUE, const rb_code_location_t*);
 #endif
 
 static NODE* node_newnode(struct parser_params *, enum node_type, VALUE, VALUE, VALUE, const rb_code_location_t*);
@@ -11660,6 +11662,20 @@ local_tbl(struct parser_params *p, VALUE *tmp)
 
     return buf;
 }
+
+static NODE*
+node_newnode_with_locals(struct parser_params *p, enum node_type type, VALUE a1, VALUE a2, const rb_code_location_t *loc)
+{
+    ID *a0;
+    NODE *n;
+    VALUE tbl = 0;
+
+    a0 = local_tbl(p, &tbl);
+    n = NEW_NODE(type, a0, a1, a2, loc);
+    tbl && RB_OBJ_WRITTEN(p->ast, Qnil, tbl);
+    return n;
+}
+
 #endif
 
 static void