include: Drop update.h

update.h is a convenience header to include headers commonly needed in
update code.  The price for the convenience is superfluous recompiles.
Include necessary headers directly, and drop update.h

Signed-off-by: Markus Armbruster <armbru@pond.sub.org>

src/lib/update/main.c

@@ -38,11 +38,13 @@
 #include <sys/resource.h>
 #include "budg.h"
 #include "empthread.h"
+#include "file.h"
 #include "game.h"
 #include "journal.h"
+#include "optlist.h"
+#include "prototypes.h"
 #include "server.h"
 #include "unit.h"
-#include "update.h"
 
 int money[MAXNOC];
 int pops[MAXNOC];