atftp: fix compilation with newer musl

Added missing header for __THROW.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

net/atftp/Makefile

@@ -8,7 +8,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=atftp
 PKG_VERSION:=0.7.2
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=@SF/$(PKG_NAME)

net/atftp/patches/04-cdefs.patch

@@ -0,0 +1,22 @@
+--- a/argz.h
++++ b/argz.h
+@@ -39,6 +39,7 @@
+ #define _ARGZ_H	1
+ 
+ #include <features.h>
++#include <sys/cdefs.h>
+ 
+ #define __need_error_t
+ #include <errno.h>
+@@ -76,9 +77,9 @@ extern error_t argz_create_sep (__const char *__restrict __string,
+ 
+ /* Returns the number of strings in ARGZ.  */
+ extern size_t __argz_count (__const char *__argz, size_t __len)
+-     __THROW __attribute_pure__;
++     __THROW;
+ extern size_t argz_count (__const char *__argz, size_t __len)
+-     __THROW __attribute_pure__;
++     __THROW;
+ 
+ /* Puts pointers to each string in ARGZ into ARGV, which must be large enough
+    to hold them all.  */