Avoid unused variables and warnings when building against OpenSSL 1.1

lib/internal.c

@@ -513,7 +513,6 @@ setting_bool_t _get_bool_config(const char *sz_setting) {
   char *psz_value = 0;
   char sz_name[256] = { 0 };
   char sz_value[256] = { 0 };
-  size_t i = 0;
   FILE *pf = 0;
 
   if ((pf = fopen(_CONFIG_FILE, "r"))) {

lib/util.c

@@ -1329,7 +1329,6 @@ uint32_t ykpiv_util_slot_object(uint8_t slot) {
 ykpiv_rc _ykpiv_util_get_serial(ykpiv_state *state, uint32_t *p_serial, bool f_force) {
   ykpiv_rc res = YKPIV_OK;
   APDU apdu;
-  const uint8_t templ[] = { 0, YKPIV_INS_SELECT_APPLICATION, 0x04, 0 };
   const uint8_t yk_applet[] = { 0xa0, 0x00, 0x00, 0x05, 0x27, 0x20, 0x01, 0x01 };
   unsigned char data[0xff];
   uint32_t recv_len = sizeof(data);

lib/ykpiv.c

@@ -1493,7 +1493,6 @@ Cleanup:
 
 ykpiv_rc ykpiv_attest(ykpiv_state *state, const unsigned char key, unsigned char *data, size_t *data_len) {
   ykpiv_rc res;
-  bool ret = false;
   unsigned char templ[] = {0, YKPIV_INS_ATTEST, key, 0};
   int sw;
   unsigned long ul_data_len;