Fix error handlings for fputs().

src/dump.c

@@ -996,13 +996,21 @@ mrb_dump_irep_cfunc(mrb_state *mrb, mrb_irep *irep, int debug_info, FILE *fp, co
       return MRB_DUMP_WRITE_FAULT;
     }
     while (bin_idx < bin_size) {
-      if (bin_idx % 16 == 0) fputs("\n", fp);
+      if (bin_idx % 16 == 0) {
+        if (fputs("\n", fp) == EOF) {
+          mrb_free(mrb, bin);
+          return MRB_DUMP_WRITE_FAULT;
+        }
+      }
       if (fprintf(fp, "0x%02x,", bin[bin_idx++]) < 0) {
         mrb_free(mrb, bin);
         return MRB_DUMP_WRITE_FAULT;
       }
     }
-    fputs("\n};\n", fp);
+    if (fputs("\n};\n", fp) == EOF) {
+      mrb_free(mrb, bin);
+      return MRB_DUMP_WRITE_FAULT;
+    }
   }
 
   mrb_free(mrb, bin);