Fixed C example

dim_plugins/example_c/src/main.c

@@ -1,6 +1,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <assert.h>
+#include <string.h>
 // Only use this define once, cause it defines funcitons
 #define PLUG_IMPL
 #include "dim_sdk.h"
@@ -38,7 +39,9 @@ int plug_post_reload(void *state) {
 }
 
 int plug_on_msg(plug_msg_t* msg) {
+    if (strcmp(msg->name, "poll") == 0) {
         snprintf(p->ctx.buf, BUF_SZ, "Hello from C! (%d)", p->count++);
+    }
     return 0;
 }