By my count there are 18 callers of CacheRegisterSyscacheCallback in the
core code in HEAD, so we are potentially leaving as few as 2 slots for any
add-on code to use (though possibly not all these callers would actually
activate in any particular session). That doesn't seem like a lot of
headroom, so let's pump it up a little.
* assumes there won't be very many of these at once; could improve if needed.
*/
-#define MAX_SYSCACHE_CALLBACKS 20
+#define MAX_SYSCACHE_CALLBACKS 32
#define MAX_RELCACHE_CALLBACKS 5
static struct SYSCACHECALLBACK