tcp.h only required for musl libc

package/iptables/patches/patch-include_linux_netfilter_xt_osf_h

@@ -1,10 +1,12 @@
 --- iptables-1.4.20.orig/include/linux/netfilter/xt_osf.h	2013-08-06 17:48:43.000000000 +0200
-+++ iptables-1.4.20/include/linux/netfilter/xt_osf.h	2013-08-15 17:04:26.116554236 +0200
-@@ -21,6 +21,7 @@
++++ iptables-1.4.20/include/linux/netfilter/xt_osf.h	2013-09-04 11:34:30.000000000 +0200
+@@ -21,6 +21,9 @@
  #define _XT_OSF_H
  
  #include <linux/types.h>
++#if !defined(__GLIBC__)
 +#include <linux/tcp.h>
++#endif
  
  #define MAXGENRELEN		32