[PATCH] Fix: rseq uapi: Adapt header includes to follow glibc header changes

[Mathieu Desnoyers]

With "recent" glibc headers, using <sys/types.h> with __GNU_SOURCE fails
to have __u32 and others types needed by the rseq.h uapi header file.
Include ctype.h and asm/types.h to fix this. Add a __KERNEL__ #ifdef to
select the kernel vs userspace header includes.

Also, remove the now unneeded asm/byteorder.h include, since it also
causes its own build issues with "recent" glibc headers.

I'm cautiously using the term "recent" glibc here because I don't know
exactly in which glibc versions those changes happened. Steven
reproduced this issue with glibc 2.37 on Debian.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Reported-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Cc: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Cc: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
 include/uapi/linux/rseq.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/include/uapi/linux/rseq.h b/include/uapi/linux/rseq.h
index c233aae5eac9..0f9cd8211ff0 100644
--- a/include/uapi/linux/rseq.h
+++ b/include/uapi/linux/rseq.h
@@ -10,8 +10,12 @@
  * Copyright (c) 2015-2018 Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
  */
 
-#include <linux/types.h>
-#include <asm/byteorder.h>
+#ifdef __KERNEL__
+# include <linux/types.h>
+#else
+# include <ctype.h>
+# include <asm/types.h>
+#endif
 
 enum rseq_cpu_id_state {
 	RSEQ_CPU_ID_UNINITIALIZED		= -1,
-- 
2.39.2