move to stock esp_http_server but keep it under control

- means 3 sockets are used (data + 2 for control)
- but LRU is activated (uses the 2 extra sockets to wake from select)
- backlog is just 1 (listen)
- only 3 sockets can be consumed before LRU activates
- for now, connections are kept-alive

components/esp_http_server/osal.h

@@ -0,0 +1,68 @@
+// Copyright 2018 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef _OSAL_H_
+#define _OSAL_H_
+
+#include <freertos/FreeRTOS.h>
+#include <freertos/task.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <esp_timer.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define OS_SUCCESS ESP_OK
+#define OS_FAIL    ESP_FAIL
+
+typedef TaskHandle_t othread_t;
+
+static inline int httpd_os_thread_create(othread_t *thread,
+                                 const char *name, uint16_t stacksize, int prio,
+                                 void (*thread_routine)(void *arg), void *arg,
+                                 BaseType_t core_id)
+{
+	StaticTask_t *xTaskBuffer = (StaticTask_t*) heap_caps_malloc(sizeof(StaticTask_t), (MALLOC_CAP_INTERNAL|MALLOC_CAP_8BIT));
+	StackType_t *xStack = heap_caps_malloc(stacksize,(MALLOC_CAP_SPIRAM|MALLOC_CAP_8BIT));
+
+	*thread = xTaskCreateStaticPinnedToCore(thread_routine, name, stacksize, arg, prio, xStack,xTaskBuffer,core_id);
+    if (*thread) {
+        return OS_SUCCESS;
+    }
+    return OS_FAIL;
+}
+
+/* Only self delete is supported */
+static inline void httpd_os_thread_delete(void)
+{
+    vTaskDelete(xTaskGetCurrentTaskHandle());
+}
+
+static inline void httpd_os_thread_sleep(int msecs)
+{
+    vTaskDelay(msecs / portTICK_RATE_MS);
+}
+
+static inline othread_t httpd_os_thread_handle(void)
+{
+    return xTaskGetCurrentTaskHandle();
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ! _OSAL_H_ */