Issue #13324: fcntlmodule: Add the F_NOCACHE flag. Patch by Alex Stewart.

Misc/ACKS

@@ -919,6 +919,7 @@ Joel Stanley
 Oliver Steele
 Greg Stein
 Chris Stern
+Alex Stewart
 Victor Stinner
 Richard Stoakley
 Peter Stoehr

Modules/fcntlmodule.c

@@ -540,10 +540,13 @@ all_ins(PyObject* d)
     if (ins(d, "F_SHLCK", (long)F_SHLCK)) return -1;
 #endif
 
-/* OS X (and maybe others) let you tell the storage device to flush to physical media */
+/* OS X specifics */
 #ifdef F_FULLFSYNC
     if (ins(d, "F_FULLFSYNC", (long)F_FULLFSYNC)) return -1;
 #endif
+#ifdef F_NOCACHE
+    if (ins(d, "F_NOCACHE", (long)F_NOCACHE)) return -1;
+#endif
 
 /* For F_{GET|SET}FL */
 #ifdef FD_CLOEXEC