[libc] Pull more definitions from linux/stat.h (llvm#67071)

For file handling, we need more definitions from
linux/stat.h, so this pulls them in. It also adjusts other definitions
to match the kernel's exactly [NFC] so that it's easy to verify that
there's been no divergence one day when it's time to use linux/stat.h
directly.

Tested:
check-libc

Author: kaladron

libc/include/llvm-libc-macros/linux/sys-stat-macros.h

@@ -9,20 +9,40 @@
 #ifndef __LLVM_LIBC_MACROS_LINUX_SYS_STAT_MACROS_H
 #define __LLVM_LIBC_MACROS_LINUX_SYS_STAT_MACROS_H
 
-// File mode flags
-#define S_IRWXU 0700
-#define S_IRUSR 0400
-#define S_IWUSR 0200
-#define S_IXUSR 0100
-#define S_IRWXG 070
-#define S_IRGRP 040
-#define S_IWGRP 020
-#define S_IXGRP 010
-#define S_IRWXO 07
-#define S_IROTH 04
-#define S_IWOTH 02
-#define S_IXOTH 01
-#define S_ISUID 04000
-#define S_ISGID 02000
+// Definitions from linux/stat.h
+#define S_IFMT  00170000
+#define S_IFSOCK 0140000
+#define S_IFLNK  0120000
+#define S_IFREG  0100000
+#define S_IFBLK  0060000
+#define S_IFDIR  0040000
+#define S_IFCHR  0020000
+#define S_IFIFO  0010000
+#define S_ISUID  0004000
+#define S_ISGID  0002000
+#define S_ISVTX  0001000
+
+#define S_ISLNK(m)      (((m) & S_IFMT) == S_IFLNK)
+#define S_ISREG(m)      (((m) & S_IFMT) == S_IFREG)
+#define S_ISDIR(m)      (((m) & S_IFMT) == S_IFDIR)
+#define S_ISCHR(m)      (((m) & S_IFMT) == S_IFCHR)
+#define S_ISBLK(m)      (((m) & S_IFMT) == S_IFBLK)
+#define S_ISFIFO(m)     (((m) & S_IFMT) == S_IFIFO)
+#define S_ISSOCK(m)     (((m) & S_IFMT) == S_IFSOCK)
+
+#define S_IRWXU 00700
+#define S_IRUSR 00400
+#define S_IWUSR 00200
+#define S_IXUSR 00100
+
+#define S_IRWXG 00070
+#define S_IRGRP 00040
+#define S_IWGRP 00020
+#define S_IXGRP 00010
+
+#define S_IRWXO 00007
+#define S_IROTH 00004
+#define S_IWOTH 00002
+#define S_IXOTH 00001
 
 #endif // __LLVM_LIBC_MACROS_LINUX_SYS_STAT_MACROS_H