add TLS support

tutorials/websocket/websocket-server/Makefile

@@ -6,6 +6,7 @@ CFLAGS = -W -Wall -Wextra -g -I.  # Build options
 
 # Mongoose build options. See https://mongoose.ws/documentation/#build-options
 CFLAGS_MONGOOSE += -DMG_ENABLE_LINES
+CFLAGS_EXTRA ?= -DMG_TLS=MG_TLS_BUILTIN
 
 ifeq ($(OS),Windows_NT)   # Windows settings. Assume MinGW compiler. To use VC: make CC=cl CFLAGS=/MD OUT=/Feprog.exe
   PROG ?= example.exe           # Use .exe suffix for the binary