linux: use sys/stat.h instead of linux/stat.h

glibc includes linux/stat.h for statx, but musl defines its own statx
struct and associated constants, which does not include STATX_MNT_ID
yet. Thus, including linux/stat.h directly should be avoided for
maximum libc compatibility.

Tested on:
  - glibc: x86_64, i686, aarch64, armv7l, armv6l
  - musl: x86_64, aarch64, armv7l, armv6l

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Tested-By: Achill Gilgenast <achill@achill.org>

Closes #17675
(cherry picked from commit ccf5a8a)

Signed-off-by: classabbyamp <dev@placeviolette.net>
Signed-off-by: Alexander Moch <mail@alexmoch.com>
Co-authored-by: classabbyamp <5366828+classabbyamp@users.noreply.github.com>

Author: alex-moch

config/user-statx.m4

@@ -2,7 +2,7 @@ dnl #
 dnl # Check for statx() function and STATX_MNT_ID availability
 dnl #
 AC_DEFUN([ZFS_AC_CONFIG_USER_STATX], [
-	AC_CHECK_HEADERS([linux/stat.h],
+	AC_CHECK_HEADERS([sys/stat.h],
 		[have_stat_headers=yes],
 		[have_stat_headers=no])
 
@@ -14,7 +14,7 @@ AC_DEFUN([ZFS_AC_CONFIG_USER_STATX], [
 			AC_MSG_CHECKING([for STATX_MNT_ID])
 			AC_COMPILE_IFELSE([
 				AC_LANG_PROGRAM([[
-					#include <linux/stat.h>
+					#include <sys/stat.h>
 				]], [[
 					struct statx stx;
 					int mask = STATX_MNT_ID;
@@ -29,6 +29,6 @@ AC_DEFUN([ZFS_AC_CONFIG_USER_STATX], [
 			])
 		])
 	], [
-		AC_MSG_WARN([linux/stat.h not found; skipping statx support])
+		AC_MSG_WARN([sys/stat.h not found; skipping statx support])
 	])
 ])  dnl end AC_DEFUN

include/os/linux/spl/sys/stat.h

@@ -24,6 +24,6 @@
 #ifndef _SPL_STAT_H
 #define	_SPL_STAT_H
 
-#include <linux/stat.h>
+#include <sys/stat.h>
 
 #endif /* SPL_STAT_H */

lib/libspl/include/os/linux/sys/stat.h

@@ -32,7 +32,7 @@
 
 #ifdef HAVE_STATX
 #include <fcntl.h>
-#include <linux/stat.h>
+#include <sys/stat.h>
 #endif
 
 /*