trunk only: preserving context (src files)

Pat Rankin wrote:
> collect them all into some new struct and
> save that separately rather than jamming more non-option stuff
> into struct flags.

This patch:
- collects all context/tracking related fields from flags
  into a new structure called "context."
It also adds the following to the new structure:
- stethoscope turn support
- victual support
- tin support

src/options.c

@@ -524,8 +524,6 @@ initoptions()
 		warnsyms[i] = def_warnsyms[i].sym;
 	iflags.bouldersym = 0;
 	iflags.travelcc.x = iflags.travelcc.y = -1;
-	flags.warnlevel = 1;
-	flags.warntype = 0L;
 
      /* assert( sizeof flags.inv_order == sizeof def_inv_order ); */
 	(void)memcpy((genericptr_t)flags.inv_order,
@@ -2162,7 +2160,7 @@ goodfruit:
 			 || (boolopt[i].addr) == &flags.showscore
 #endif
 			    )
-			    flags.botl = TRUE;
+			    context.botl = TRUE;
 
 			else if ((boolopt[i].addr) == &flags.invlet_constant) {
 			    if (flags.invlet_constant) reassign();