Adding cython v0.20.2 in third-party.

third_party/cython/src/Cython/Includes/libc/errno.pxd

Index: third_party/cython/src/Cython/Includes/libc/errno.pxd
diff --git a/third_party/cython/src/Cython/Includes/libc/errno.pxd b/third_party/cython/src/Cython/Includes/libc/errno.pxd
new file mode 100644
index 0000000000000000000000000000000000000000..936873da116749b33c374f79d7fc007460825f4b
--- /dev/null
+++ b/third_party/cython/src/Cython/Includes/libc/errno.pxd
@@ -0,0 +1,127 @@
+# 7.5 Errors <errno.h>
+
+cdef extern from "errno.h" nogil:
+    enum:
+        EPERM
+        ENOENT
+        ESRCH
+        EINTR
+        EIO
+        ENXIO
+        E2BIG
+        ENOEXEC
+        EBADF
+        ECHILD
+        EAGAIN
+        ENOMEM
+        EACCES
+        EFAULT
+        ENOTBLK
+        EBUSY
+        EEXIST
+        EXDEV
+        ENODEV
+        ENOTDIR
+        EISDIR
+        EINVAL
+        ENFILE
+        EMFILE
+        ENOTTY
+        ETXTBSY
+        EFBIG
+        ENOSPC
+        ESPIPE
+        EROFS
+        EMLINK
+        EPIPE
+        EDOM
+        ERANGE
+        EDEADLOCK
+        ENAMETOOLONG
+        ENOLCK
+        ENOSYS
+        ENOTEMPTY
+        ELOOP
+        ENOMSG
+        EIDRM
+        ECHRNG
+        EL2NSYNC
+        EL3HLT
+        EL3RST
+        ELNRNG
+        EUNATCH
+        ENOCSI
+        EL2HLT
+        EBADE
+        EBADR
+        EXFULL
+        ENOANO
+        EBADRQC
+        EBADSLT
+        EBFONT
+        ENOSTR
+        ENODATA
+        ETIME
+        ENOSR
+        ENONET
+        ENOPKG
+        EREMOTE
+        ENOLINK
+        EADV
+        ESRMNT
+        ECOMM
+        EPROTO
+        EMULTIHOP
+        EDOTDOT
+        EBADMSG
+        EOVERFLOW
+        ENOTUNIQ
+        EBADFD
+        EREMCHG
+        ELIBACC
+        ELIBBAD
+        ELIBSCN
+        ELIBMAX
+        ELIBEXEC
+        EILSEQ
+        ERESTART
+        ESTRPIPE
+        EUSERS
+        ENOTSOCK
+        EDESTADDRREQ
+        EMSGSIZE
+        EPROTOTYPE
+        ENOPROTOOPT
+        EPROTONOSUPPORT
+        ESOCKTNOSUPPORT
+        EOPNOTSUPP
+        EPFNOSUPPORT
+        EAFNOSUPPORT
+        EADDRINUSE
+        EADDRNOTAVAIL
+        ENETDOWN
+        ENETUNREACH
+        ENETRESET
+        ECONNABORTED
+        ECONNRESET
+        ENOBUFS
+        EISCONN
+        ENOTCONN
+        ESHUTDOWN
+        ETOOMANYREFS
+        ETIMEDOUT
+        ECONNREFUSED
+        EHOSTDOWN
+        EHOSTUNREACH
+        EALREADY
+        EINPROGRESS
+        ESTALE
+        EUCLEAN
+        ENOTNAM
+        ENAVAIL
+        EISNAM
+        EREMOTEIO
+        EDQUOT
+
+    int errno
+