Improve perf_event_open argument decoding

* configure.ac (AC_CHECK_HEADERS): Add linux/perf_event.h.
* desc.c [HAVE_LINUX_PERF_EVENT_H]: Include <linux/perf_event.h>.
(perf_event_open_flags): New xlat structure.
(sys_perf_event_open): New function.
* linux/dummy.h (sys_perf_event_open): Remove.
* linux/syscall.h (sys_perf_event_open): New prototype.

Signed-off-by: Ben Noordhuis <info@bnoordhuis.nl>
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
diff --git a/configure.ac b/configure.ac
index f44eaf1..80be383 100644
--- a/configure.ac
+++ b/configure.ac
@@ -196,6 +196,7 @@
 	ioctls.h
 	libaio.h
 	linux/capability.h
+	linux/perf_event.h
 	linux/ptrace.h
 	linux/utsname.h
 	mqueue.h