Fix compile error in net.c with musl libc

fixes #278
diff --git a/ChangeLog b/ChangeLog
index 6f8181b..05450f6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 PolarSSL ChangeLog
 
+= Version 1.2.17 released 2015-10-xx
+
+Bugfix
+   * Fix compile error in net.c with musl libc. Found and patch provided by
+     zhasha (#278).
+
 = Version 1.2.16 released 2015-09-17
 
 Security
diff --git a/library/net.c b/library/net.c
index 0e5edc0..2685d6a 100644
--- a/library/net.c
+++ b/library/net.c
@@ -268,7 +268,7 @@
     struct sockaddr_in client_addr;
 
 #if defined(__socklen_t_defined) || defined(_SOCKLEN_T) ||  \
-    defined(_SOCKLEN_T_DECLARED)
+    defined(_SOCKLEN_T_DECLARED) || defined(__DEFINED_socklen_t)
     socklen_t n = (socklen_t) sizeof( client_addr );
 #else
     int n = (int) sizeof( client_addr );