hand slip when naming objects (trunk only)

From a bug report, the text change applied
when you try to give an artifact's name to am item of that artifact's type
would choose a letter from 'a' through 'y' when replacing the randomly
selected target letter.  Rather than fixing the off by one bug which
prevented 'z' from being chosen, this switches to the existing routine
used for mangling engravings.  (Unfortunately the fix is not as simple as
first expected, because wipeout_text() doesn't guarantee to change text
which has spaces in it and all the quest artifact names have those.)

doc/fixes35.0

@@ -292,6 +292,7 @@ give "shuddering vibrations" feedback if breaking a poly wand uses up items
 if polymorph causes a monster to drop items, they won't be used up via
 	shuddering vibrations or as golem creation fodder
 monsters who ate green slime corpses weren't turned into green slime
+"hand slip" while naming an object would never pick 'z' as a substitute letter
 
 
 Platform- and/or Interface-Specific Fixes

src/do_name.c

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)do_name.c	3.5	2007/05/12	*/
+/*	SCCS Id: @(#)do_name.c	3.5	2008/11/02	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -386,7 +386,7 @@ void
 do_oname(obj)
 register struct obj *obj;
 {
-	char buf[BUFSZ], qbuf[QBUFSZ];
+	char buf[BUFSZ], bufcpy[BUFSZ], qbuf[QBUFSZ];
 	const char *aname;
 	short objtyp;
 
@@ -406,13 +406,22 @@ register struct obj *obj;
 		pline_The("artifact seems to resist the attempt.");
 		return;
 	} else if (restrict_name(obj, buf) || exist_artifact(obj->otyp, buf)) {
-		int n = rn2((int)strlen(buf));
+		/* this used to change one letter, substituting a value
-		register char c1, c2;
+		   of 'a' through 'y' (due to an off by one error, 'z'
-
+		   would never be selected) and then force that to
-		c1 = lowc(buf[n]);
+		   upper case if such was the case of the input;
-		do c2 = 'a' + rn2('z'-'a'); while (c1 == c2);
+		   now, the hand slip scuffs one or two letters as if
-		buf[n] = (buf[n] == c1) ? c2 : highc(c2);  /* keep same case */
+		   the text had been trodden upon, sometimes picking
-		pline("While engraving your %s slips.", body_part(HAND));
+		   punctuation instead of an arbitrary letter;
+		   unfortunately, we have to cover the possibility of
+		   it targetting spaces so failing to make any change
+		   (we know that it must eventually target a nonspace
+		   because buf[] matches a valid artifact name) */
+		Strcpy(bufcpy, buf);
+		do {
+		    wipeout_text(buf, rnd(2), (unsigned)0);
+		} while (!strcmp(buf, bufcpy));
+		pline("While engraving, your %s slips.", body_part(HAND));
 		display_nhwindow(WIN_MESSAGE, FALSE);
 		You("engrave: \"%s\".",buf);
 	}