bcc: fix musl

Signed-off-by: Jürgen Buchmüller <pullmoll@t-online.de>

srcpkgs/bcc/patches/musl.patch

@@ -48,3 +48,15 @@
  #include <arpa/inet.h>
  #include <errno.h>
  #include <fcntl.h>
+--- src/cc/libbpf/src/hashmap.h.orig	2019-05-29 19:27:27.000000000 +0200
++++ src/cc/libbpf/src/hashmap.h	2019-06-01 23:57:31.458324372 +0200
+@@ -10,6 +10,9 @@
+ 
+ #include <stdbool.h>
+ #include <stddef.h>
++#if !defined(__GLIBC__)
++#include <bits/reg.h>	/* for __WORDSIZE */
++#endif
+ #include "libbpf_internal.h"
+ 
+ static inline size_t hash_bits(size_t h, int bits)