Fix compilation with 4.x kernel headers

- Fallback to __NR_stat syscall in ld.so if we use 4.x kernel headers.
4.x kernel doesn't support 64-bit time so we can use old syscall
- Add preprocessor conditions to have fstat64 and fstatat64 in libc
with old kernel headers

Signed-off-by: Dmitry Chestnykh <dm.chestnykh@gmail.com>

ldso/include/dl-syscall.h

@@ -17,6 +17,8 @@ extern int _dl_errno;
 #define __set_errno(X) {(_dl_errno) = (X);}
 #endif
 
+#include <linux/version.h>
+
 /* Pull in the arch specific syscall implementation */
 #include <dl-syscalls.h>
 /*  For MAP_ANONYMOUS -- differs between platforms */
@@ -139,7 +141,7 @@ static __always_inline int _dl_stat(const char *file_name,
 {
 	return _dl_newfstatat(AT_FDCWD, file_name, buf, 0);
 }
-#elif defined __NR_stat && (!defined(__UCLIBC_USE_TIME64__) || defined(__sparc__))
+#elif defined __NR_stat && (!defined(__UCLIBC_USE_TIME64__) || defined(__sparc__)) || (LINUX_VERSION_CODE <= KERNEL_VERSION(5,1,0))
 # define __NR__dl_stat __NR_stat
 static __always_inline _syscall2(int, _dl_stat, const char *, file_name,
                         struct stat *, buf)

libc/sysdeps/linux/common/fstat64.c

@@ -8,8 +8,9 @@
 
 #include <_lfs_64.h>
 #include <sys/syscall.h>
+#include <linux/version.h>
 
-#if defined(__NR_fstat64) && !defined(__UCLIBC_USE_TIME64__)
+#if defined(__NR_fstat64) && (!defined(__UCLIBC_USE_TIME64__) || LINUX_VERSION_CODE <= KERNEL_VERSION(5,1,0))
 # include <unistd.h>
 # include <sys/stat.h>
 # include "xstatconv.h"

libc/sysdeps/linux/common/fstatat64.c

@@ -9,6 +9,7 @@
 #include <_lfs_64.h>
 #include <bits/wordsize.h>
 #include <sys/syscall.h>
+#include <linux/version.h>
 
 #if defined __mips__
 # include <sgidefs.h>
@@ -23,7 +24,7 @@
 # define __NR_fstatat64 __NR_newfstatat
 #endif
 
-#if defined(__NR_fstatat64) && !defined(__UCLIBC_USE_TIME64__)
+#if defined(__NR_fstatat64) && (!defined(__UCLIBC_USE_TIME64__)  || LINUX_VERSION_CODE <= KERNEL_VERSION(5,1,0))
 # include <sys/stat.h>
 # include "xstatconv.h"
 int fstatat64(int fd, const char *file, struct stat64 *buf, int flag)