Fix Travis CI

src/backtrace.c

@@ -108,11 +108,11 @@ each_backtrace(mrb_state *mrb, mrb_int ciidx, mrb_code *pc0, each_backtrace_func
 
   for (i = ciidx; i >= 0; i--) {
     struct backtrace_location_raw loc;
-    loc.lineno = -1;
-    
     mrb_callinfo *ci;
     mrb_irep *irep;
     mrb_code *pc;
+    
+    loc.lineno = -1;
 
     ci = &mrb->c->cibase[i];