Re-work of thread model

ext/lwip-contrib.patch

@@ -1,32 +0,0 @@
-diff --git a/ports/unix/port/include/arch/cc.h b/ports/unix/port/include/arch/cc.h
-index 80b37d8..ae46d76 100644
---- a/ports/unix/port/include/arch/cc.h
-+++ b/ports/unix/port/include/arch/cc.h
-@@ -32,6 +32,8 @@
- #ifndef LWIP_ARCH_CC_H
- #define LWIP_ARCH_CC_H
- 
-+#include "include/Debug.hpp" // libzt
-+
- /* see https://sourceforge.net/p/predef/wiki/OperatingSystems/ */
- #if defined __ANDROID__
- #define LWIP_UNIX_ANDROID
-@@ -65,7 +67,7 @@
- #endif
- 
- #if defined(LWIP_UNIX_ANDROID) && defined(FD_SET)
--typedef __kernel_fd_set fd_set;
-+//typedef __kernel_fd_set fd_set;
- #endif
- 
- #if defined(LWIP_UNIX_MACH)
-@@ -81,6 +83,9 @@ typedef struct sio_status_s sio_status_t;
- #define sio_fd_t sio_status_t*
- #define __sio_fd_t_defined
- 
-+// Comment out the following line to use lwIP's default diagnostic printing routine
-+#define LWIP_PLATFORM_DIAG(x)    do {DEBUG_INFO x;} while(0)
-+
- typedef unsigned int sys_prot_t;
- 
- #endif /* LWIP_ARCH_CC_H */