Adding cython v0.20.2 in third-party.

third_party/cython/src/Cython/Includes/posix/fcntl.pxd

Index: third_party/cython/src/Cython/Includes/posix/fcntl.pxd
diff --git a/third_party/cython/src/Cython/Includes/posix/fcntl.pxd b/third_party/cython/src/Cython/Includes/posix/fcntl.pxd
new file mode 100644
index 0000000000000000000000000000000000000000..b71d31176c61e76c7c35314ba856d6d606b387d1
--- /dev/null
+++ b/third_party/cython/src/Cython/Includes/posix/fcntl.pxd
@@ -0,0 +1,67 @@
+# http://www.opengroup.org/onlinepubs/009695399/basedefs/fcntl.h.html
+
+cdef extern from "fcntl.h" nogil:
+
+    enum: F_DUPFD
+    enum: F_GETFD
+    enum: F_SETFD
+    enum: F_GETFL
+    enum: F_SETFL
+    enum: F_GETLK
+    enum: F_SETLK
+    enum: F_SETLKW
+    enum: F_GETOWN
+    enum: F_SETOWN
+
+    enum: FD_CLOEXEC
+
+    enum: F_RDLCK
+    enum: F_UNLCK
+    enum: F_WRLCK
+
+    enum: SEEK_SET
+    enum: SEEK_CUR
+    enum: SEEK_END
+
+    enum: O_CREAT
+    enum: O_EXCL
+    enum: O_NOCTTY
+    enum: O_TRUNC
+
+    enum: O_APPEND
+    enum: O_DSYNC
+    enum: O_NONBLOCK
+    enum: O_RSYNC
+    enum: O_SYNC
+
+    enum: O_ACCMODE # O_RDONLY|O_WRONLY|O_RDWR
+
+    enum: O_RDONLY
+    enum: O_WRONLY
+    enum: O_RDWR
+
+    enum: S_IFMT
+    enum: S_IFBLK
+    enum: S_IFCHR
+    enum: S_IFIFO
+    enum: S_IFREG
+    enum: S_IFDIR
+    enum: S_IFLNK
+    enum: S_IFSOCK
+
+    ctypedef int    mode_t
+    ctypedef signed pid_t
+    ctypedef signed off_t
+
+    struct flock:
+        short l_type
+        short l_whence
+        off_t l_start
+        off_t l_len
+        pid_t l_pid
+
+    int creat(char *, mode_t)
+    int fcntl(int, int, ...)
+    int open(char *, int, ...)
+    #int open (char *, int, mode_t)
+