Files httpc_client.h and httpc_client.c both declare httpc_state_t as a typedef.  GCC, when used with the -std=gnu99 flag, fails with the error:

     lwip/src/apps/http/http_client.c:153:3: error: redefinition of typedef ‘httpc_state_t’ [-Werror=pedantic]
      } httpc_state_t;

The attached script is the make instruction to compile http_client.c.  It differs from what cmake generates by default only in the addition of the -std=gnu99 flag. Run it from the root directory of lwip to see the full diagnostic messages.

Can the definition of the structure be moved from http_client.c to http_client.h?