Fixes for stdlib.h inclusion

Refs:
http://esp32.com/viewtopic.php?f=13&t=550
http://esp32.com/viewtopic.php?f=13&t=551

rmt.c should include stdlib.h for malloc, esp_bignum,c &
https_request_main.c for abort().

FreeRTOSConfig.h is only including stdlib if
CONFIG_FREERTOS_ASSERT_ON_UNTESTED_FUNCTION is set. However, it is
included for abort() so needs to be included whenever
CONFIG_FREERTOS_ASSERT_FAIL_ABORT is set.

This change includes unconditionally in FreeRTOSConfig.h. This is to
avoid this kind of bug where compiler errors are dependent on config. I
suggest we don't change this to be more selective until we have 'make
randomconfig' style tests in CI.

components/driver/rmt.c

@@ -13,6 +13,7 @@
 // limitations under the License.
 #include <esp_types.h>
 #include <string.h>
+#include <stdlib.h>
 #include "freertos/FreeRTOS.h"
 #include "freertos/semphr.h"
 #include "freertos/xtensa_api.h"

components/freertos/include/freertos/FreeRTOSConfig.h

@@ -108,6 +108,7 @@
 
 /* configASSERT behaviour */
 #ifndef __ASSEMBLER__
+#include <stdlib.h> /* for abort() */
 #include "rom/ets_sys.h"
 
 #if defined(CONFIG_FREERTOS_ASSERT_DISABLE)
@@ -126,8 +127,6 @@
 #endif
 
 #if CONFIG_FREERTOS_ASSERT_ON_UNTESTED_FUNCTION
-#include <stdlib.h>
-#include "rom/ets_sys.h"
 #define UNTESTED_FUNCTION() { ets_printf("Untested FreeRTOS function %s\r\n", __FUNCTION__); configASSERT(false); } while(0)
 #else
 #define UNTESTED_FUNCTION()

components/mbedtls/port/esp_bignum.c

@@ -25,6 +25,7 @@
 #include <malloc.h>
 #include <limits.h>
 #include <assert.h>
+#include <stdlib.h>
 #include "mbedtls/bignum.h"
 #include "rom/bigint.h"
 #include "soc/hwcrypto_reg.h"

examples/04_https_request/main/https_request_main.c

@@ -22,6 +22,7 @@
  * limitations under the License.
  */
 #include <string.h>
+#include <stdlib.h>
 #include "freertos/FreeRTOS.h"
 #include "freertos/task.h"
 #include "freertos/event_groups.h"