Add JWT Bearer Authentication support and tutorial

src/util.c

@@ -25,6 +25,14 @@ uint64_t mg_timegm(unsigned int year, unsigned int month, unsigned int day,
          day_secs * ((ly + 299) / 400);
 }
 
+bool mg_memeq(const void *a, const void *b, size_t n) {
+  const uint8_t *p = (const uint8_t *) a, *q = (const uint8_t *) b;
+  uint8_t r = 0;
+  size_t i;
+  for (i = 0; i < n; i++) r = (uint8_t) (r | (uint8_t) (p[i] ^ q[i]));
+  return r == 0;
+}
+
 #if MG_ENABLE_CUSTOM_RANDOM
 #else
 bool mg_random(void *buf, size_t len) {