debug/strace: fix strace 4.5.19 to properly build with latest Linux kernels

Here's a couple of patches to get strace 4.5.19 to configure and build
properly with the latest kernel headers. Not pretty, but hopefully
enough while we wait for 4.5.20 to be released.

With the current strace-4.5.19 patches I failed to get the configure
script running even on my host environment. Also, when cross building
the configure script needs to look for the proper system headers to be
able to properly set HAVE_LINUX_NETLINK_H. Otherwise you get:

[EXTRA] Building strace
[ERROR] /home/jocke/x-tools/targets/src/strace-4.5.19/net.c:976:
error: field 'nl' has incomplete type
[ERROR] make[2]: *** [net.o] Error 1
[ERROR] make[1]: *** [all] Error 2

The fix was simple, backport a change set from the git[1] tree and run
autoreconf to update the configure script.

[1] - http://strace.git.sourceforge.net/git/gitweb.cgi?p=strace/strace;a=commit;h=f0df31e71a58c6e79ba77c1a9d84b2f38d44bec7

 Dmitry V. Levin [Tue, 3 Nov 2009 16:49:49 +0000]

 Fix check for linux/netlink.h on Linux 2.6.32-rc5+

 * configure.ac (AC_CHECK_HEADERS): In check for linux/netlink.h, include 

   sys/socket.h instead of linux/socket.h beforehand.

 diff --git a/configure.ac b/configure.ac

 --- a/configure.ac

 +++ b/configure.ac

 @@ -258,7 +258,7 @@ AC_CHECK_HEADERS([ \

  ], [], [])

  AC_CHECK_HEADERS([linux/icmp.h linux/in6.h linux/netlink.h linux/if_packet.h],

                   [], [], [#include <stddef.h>

 -#include <linux/socket.h>])

 +#include <sys/socket.h>])

  AC_CHECK_HEADERS([asm/sigcontext.h], [], [], [#include <signal.h>])

  AC_CHECK_TYPES([struct sigcontext_struct,

  		struct sigcontext],,, [#include <signal.h>])