x86_64: Fix sys/stat.h

Add 64-bit stat structure mapping 64-bit stat syscall.

Change-Id: Ice517616391bee1d556b6c03e7f5ee610050e6c6
Signed-off-by: Pavel Chupin <pavel.v.chupin@intel.com>
diff --git a/libc/include/sys/stat.h b/libc/include/sys/stat.h
index 10627b9..95e83d8 100644
--- a/libc/include/sys/stat.h
+++ b/libc/include/sys/stat.h
@@ -73,6 +73,29 @@
 
     unsigned long long  st_blocks;
 };
+
+#elif __x86_64__
+struct stat {
+    unsigned long st_dev;
+    unsigned long st_ino;
+    unsigned long st_nlink;
+    unsigned int st_mode;
+    unsigned int st_uid;
+    unsigned int st_gid;
+    unsigned int __pad0;
+    unsigned long st_rdev;
+    long st_size;
+    long st_blksize;
+    long st_blocks;
+    unsigned long st_atime;
+    unsigned long st_atime_nsec;
+    unsigned long st_mtime;
+    unsigned long st_mtime_nsec;
+    unsigned long st_ctime;
+    unsigned long st_ctime_nsec;
+    long __pad3[3];
+};
+
 #else
 struct stat {
     unsigned long long  st_dev;