Add timers example to mongoose

PUBLISHED_FROM=1599cf1d06c8f177918cbcf574c28c9e93d56d39

examples/timers/Makefile

+PROG = timers
+MODULE_CFLAGS=-DMG_DISABLE_DAV
+include ../examples.mk

examples/timers/timers.c

+// Copyright (c) 2015 Cesanta Software Limited
+// All rights reserved
+
+#include "mongoose.h"
+
+static const char *s_http_port = "8000";
+static struct mg_serve_http_opts s_http_server_opts;
+
+static void ev_handler(struct mg_connection *c, int ev, void *ev_data) {
+  switch (ev) {
+    case MG_EV_HTTP_REQUEST:
+      mg_serve_http(c, (struct http_message *) ev_data, s_http_server_opts);
+      break;
+    case MG_EV_TIMER: {
+      double now = *(double *) ev_data;
+      double next = mg_set_timer(c, 0) + 0.5;
+      printf("timer event, current time: %.2lf\n", now);
+      mg_set_timer(c, next);  // Send us timer event again after 0.5 seconds
+      break;
+    }
+  }
+}
+
+int main(void) {
+  struct mg_mgr mgr;
+  struct mg_connection *c;
+
+  mg_mgr_init(&mgr, NULL);
+  c = mg_bind(&mgr, s_http_port, ev_handler);
+  if (c == NULL) {
+    printf("Cannot start on port %s\n", s_http_port);
+    return EXIT_FAILURE;
+  }
+
+  // Set up HTTP server parameters
+  mg_set_protocol_http_websocket(c);
+  s_http_server_opts.document_root = ".";  // Serve current directory
+
+  // Send us MG_EV_TIMER event after 2.5 seconds
+  mg_set_timer(c, mg_time() + 2.5);
+
+  printf("Starting on port %s, time: %.2lf\n", s_http_port, mg_time());
+  for (;;) {
+    mg_mgr_poll(&mgr, 1000);
+  }
+  mg_mgr_free(&mgr);
+
+  return EXIT_SUCCESS;
+}