thawing ice followup

Modifying an() [actually just_an()] to treat "<thickness> ice" and
"frozen <hallucinatory liquid>" as special cases which shouldn't be
prefixed with "a" or "an" affected using something like "shaved ice"
or "frozen yogurt" as named fruit.
 |a) shaved ice
 |b) frozen yogurt (weapon in hand)
now have article "a" preceding them:
 |a) a shaved ice
 |b) a frozen yogurt (weapon in hand)
However, the existing cases
 |c) iron bars
 |d) an iron bars (weapon in hand)
still get item 'c' wrong.  'd' is slightly odd but that's because the
fruit name is ambiguous as to whether it's singular or plural.

include/config.h

@@ -6,6 +6,13 @@
 #ifndef CONFIG_H /* make sure the compiler does not see the typedefs twice */
 #define CONFIG_H
 
+#define EXTRA_SANITY_CHECKS
+#define MONITOR_HEAP
+#define DUMPLOG
+#define SCORE_ON_BOTL
+#define EDIT_GETLIN
+#define LIVELOG
+
 /*
  * Section 1:   Operating and window systems selection.
  *              Select the version of the OS you are using.
@@ -582,7 +589,7 @@ typedef unsigned char uchar;
 
 /* An experimental minimalist inventory list capability under tty if you have
  * at least 28 additional rows beneath the status window on your terminal  */
-/* #define TTY_PERM_INVENT */
+#define TTY_PERM_INVENT /**/
 
 /* NetHack will execute an external program whenever a new message-window
  * message is shown.  The program to execute is given in environment variable