Index: unnethack-3.5.3/include/unixconf.h
===================================================================
--- unnethack-3.5.3.orig/include/unixconf.h	2011-05-09 16:09:49.000000000 +0400
+++ unnethack-3.5.3/include/unixconf.h	2011-05-09 16:11:35.000000000 +0400
@@ -286,7 +286,9 @@
 #endif
 #define tgetch getchar
 
-#define SHELL		/* do not delete the '!' command */
+#ifdef SHELL
+#undef SHELL		/* do not delete the '!' command */
+#endif
 
 #if defined(POSIX_TYPES) || defined(__GNUC__)
 #include <stdlib.h>
