make program_state initialization a discrete step

Having it rolled into decl_globals_init() was
causing some early options to misbehave because
those early options were trying to use program_state
fields to determine their behavior, but decl_globals_init()
was resetting the program_state fields that were being used
to do that.

include/extern.h

@@ -510,6 +510,7 @@ extern void destroy_drawbridge(coordxy, coordxy);
 
 /* ### decl.c ### */
 
+extern void program_state_init(void);
 extern void decl_globals_init(void);
 extern void sa_victual(volatile struct victual_info *);