Restructure documentation. Create two top-level sections for thread-safe and callback-style APIs.

src/core/dns.c

@@ -39,6 +39,7 @@
 
 /**
  * @defgroup dns DNS
+ * @ingroup callbackstyle_api
  *
  * Implements a DNS host name to IP address resolver.
  *

src/core/init.c

@@ -323,6 +323,7 @@
 /**
  * @ingroup lwIP
  * Initialize all modules.
+ * Use this in NO_SYS mode. Use tcpip_init() otherwise.
  */
 void
 lwip_init(void)

src/core/ip.c

@@ -38,8 +38,10 @@
 
 /**
  * @defgroup ip4 IPv4
+ * @ingroup callbackstyle_api
  *
  * @defgroup ip6 IPv6
+ * @ingroup callbackstyle_api
  * 
  * @defgroup ipaddr IP address handling
  * 

src/core/netif.c

@@ -36,6 +36,7 @@
 
 /**
  * @defgroup netif Network interface (NETIF)
+ * @ingroup callbackstyle_api
  */
 
 #include "lwip/opt.h"

src/core/raw.c

@@ -40,6 +40,7 @@
 
 /**
  * @defgroup raw_api RAW API
+ * @ingroup callbackstyle_api
  * @verbinclude "rawapi.txt"
  */