Fix more nocode_wanted jump problems

In statement expression we really mustn't emit backward jumps
under nocode_wanted (they will form infinte loops as no expressions
are evaluated).  Do-while and explicit loop with gotos weren't
handled.

tccgen.c

@@ -5605,8 +5605,9 @@ static void block(int *bsym, int *csym, int is_expr)
         skip('(');
         gsym(b);
         gexpr();
-        c = gvtst(0, 0);
-        gsym_addr(c, d);
+	c = gvtst(0, 0);
+	if (!nocode_wanted)
+	    gsym_addr(c, d);
         skip(')');
         gsym(a);
         skip(';');
@@ -5678,7 +5679,10 @@ static void block(int *bsym, int *csym, int is_expr)
             gexpr();
             if ((vtop->type.t & VT_BTYPE) != VT_PTR)
                 expect("pointer");
-            ggoto();
+	    if (!nocode_wanted)
+                ggoto();
+	    else
+	        vtop--;
         } else if (tok >= TOK_UIDENT) {
             s = label_find(tok);
             /* put forward definition if needed */
@@ -5689,7 +5693,9 @@ static void block(int *bsym, int *csym, int is_expr)
                     s->r = LABEL_FORWARD;
             }
             vla_sp_restore_root();
-            if (s->r & LABEL_FORWARD) 
+	    if (nocode_wanted)
+	      ;
+	    else if (s->r & LABEL_FORWARD)
                 s->jnext = gjmp(s->jnext);
             else
                 gjmp_addr(s->jnext);

tests/tests2/82_nocode_wanted.c

@@ -27,6 +27,36 @@ static void kb_wait_2(void)
         timeout--;
     } while (timeout);
 }
+static void kb_wait_2_1(void)
+{
+    unsigned long timeout = 2;
+    do {
+        (1 ? 
+            printf("timeout=%ld\n", timeout) :
+            ({
+                do {
+                    printf("error\n");
+		} while (1);
+            })
+        );
+        timeout--;
+    } while (timeout);
+}
+static void kb_wait_2_2(void)
+{
+    unsigned long timeout = 2;
+    do {
+        (1 ? 
+            printf("timeout=%ld\n", timeout) :
+            ({
+                label:
+                    printf("error\n");
+		goto label;
+            })
+        );
+        timeout--;
+    } while (timeout);
+}
 static void kb_wait_3(void)
 {
     unsigned long timeout = 2;
@@ -73,6 +103,8 @@ int main()
     printf("begin\n");
     kb_wait_1();
     kb_wait_2();
+    kb_wait_2_1();
+    kb_wait_2_2();
     kb_wait_3();
     kb_wait_4();
     printf("end\n");

tests/tests2/82_nocode_wanted.expect

@@ -7,4 +7,8 @@ timeout=2
 timeout=1
 timeout=2
 timeout=1
+timeout=2
+timeout=1
+timeout=2
+timeout=1
 end