mem_malloc with MEM_USE_POOLS=1: if size > size of biggest pool and custom pools (in addition to the MEM_POOLs) were defined, the first custom pool was used instead of asserting

src/core/mem.c

@@ -79,7 +79,7 @@ mem_malloc(mem_size_t size)
       break;
     }
   }
-  if (poolnr == MEMP_MAX) {
+  if (poolnr > MEMP_POOL_LAST) {
     LWIP_ASSERT("mem_malloc(): no pool is that big!", 0);
     return NULL;
   }