add command line option --showpaths

Add
	--showpaths
early option to show where NetHack is expecting to find certain files
without starting up a game. It exits afterwards.

Windows sample (for illustration only, locations may differ for you):
    Variable playground locations:
        [hackdir   ]="C:\Users\JohnDoe\NetHack\3.6\"
        [leveldir  ]="C:\Users\JohnDoe\AppData\Local\NetHack\3.6\"
        [savedir   ]="C:\Users\JohnDoe\AppData\Local\NetHack\3.6\"
        [bonesdir  ]="C:\ProgramData\NetHack\3.6\"
        [datadir   ]="C:\personal\nhdev\363\test\binary\"
        [scoredir  ]="C:\ProgramData\NetHack\3.6\"
        [lockdir   ]="C:\ProgramData\NetHack\3.6\"
        [sysconfdir]="C:\ProgramData\NetHack\3.6\"
        [configdir ]="C:\Users\JohnDoe\NetHack\3.6\"
        [troubledir]="C:\Users\JohnDoe\NetHack\3.6\"
    Your system configuration file (in sysconfdir):
        "C:\Users\JohnDoe\NetHack\3.6\sysconf"
    Your system symbols file (in sysconfdir):
        "C:\Users\JohnDoe\NetHack\3.6\symbols"
    Your personal configuration file (in configdir):
        "C:\Users\JohnDoe\NetHack\3.6\.nethackrc"

Linux (for illustration only, locations may differ for you):
    Your system configuration file:
        "/home/johndoe/nh/install/games/lib/nethackdir/sysconf"
    Your system symbols file:
        "/home/johndoe/nh/install/games/lib/nethackdir/symbols"
    Your personal configuration file:
        "/home/johndoe/.nethackrc"

src/allmain.c

@@ -767,6 +767,7 @@ const char *msg;
 static struct early_opt earlyopts[] = {
     {ARG_DEBUG, "debug", 5, TRUE},
     {ARG_VERSION, "version", 4, TRUE},
+    {ARG_SHOWPATHS, "showpaths", 9, FALSE},
 #ifdef WIN32
     {ARG_WINDOWS, "windows", 4, TRUE},
 #endif
@@ -845,6 +846,9 @@ enum earlyarg e_arg;
             early_version_info(insert_into_pastebuf);
             return 2;
         }
+        case ARG_SHOWPATHS: {
+            return 2;
+        }
 #ifdef WIN32
         case ARG_WINDOWS: {
             if (extended_opt) {

src/files.c

@@ -3197,7 +3197,13 @@ fopen_sym_file()
 {
     FILE *fp;
 
-    fp = fopen_datafile(SYMBOLS, "r", HACKPREFIX);
+    fp = fopen_datafile(SYMBOLS, "r",
+#ifdef WIN32
+                            SYSCONFPREFIX
+#else
+                            HACKPREFIX
+#endif
+                       );
 
     return fp;
 }
@@ -3966,6 +3972,98 @@ boolean wildcards;
 
 #endif /*DEBUG*/
 
+void
+reveal_paths(VOID_ARGS)
+{
+    int i;
+#define PATHBUFSZ 1024
+    char buf[PATHBUFSZ];
+#ifdef UNIX
+    char *envp, *slash, nhpath[PATHBUFSZ];
+#endif
+
+    /* write out path details  */
+#ifdef PREFIXES_IN_USE
+    raw_print("Variable playground locations:");
+    for (i = 0; i < PREFIX_COUNT; i++)
+        raw_printf("    [%-10s]=\"%s\"", fqn_prefix_names[i],
+                    fqn_prefix[i]
+                        ? fqn_prefix[i]
+                        : "not set");
+#endif
+    /* sysconf file */
+#ifdef PREFIXES_IN_USE
+    Sprintf(buf, " (in %s)",
+            fqn_prefix_names[SYSCONFPREFIX]);
+#else
+    buf[0] = '\0';
+#endif
+    raw_printf("Your system configuration file%s:", buf);
+    set_configfile_name(fqname(SYSCF_FILE, SYSCONFPREFIX, 0));
+    raw_printf("    \"%s\"", configfile);
+#ifdef UNIX
+    Strcpy(nhpath, configfile);
+    slash = rindex(nhpath, '/');
+    if (slash)
+        *slash = '\0';
+#endif
+
+    /* symbols file */
+#ifdef PREFIXES_IN_USE
+    Sprintf(buf, " (in %s)",
+#ifdef WIN32
+            fqn_prefix_names[SYSCONFPREFIX]);
+#else
+            fqn_prefix_names[HACKPREFIX]);
+#endif /* WIN32 */
+#else /* PREFIXES_IN_USE */
+    buf[0] = '\0';
+#endif
+
+    raw_printf("Your system symbols file%s:", buf);
+#ifdef UNIX
+    Sprintf(buf, "%s/%s", nhpath, SYMBOLS);
+#else
+#ifdef PREFIXES_IN_USE
+    Sprintf(buf, "%s",
+                fqname(SYMBOLS,
+#ifdef WIN32
+                        SYSCONFPREFIX, 2));
+#else
+                        HACKPREFIX, 2));
+#endif
+#endif /* PREFIXES_IN_USE */
+#endif /* UNIX */
+    raw_printf("    \"%s\"", buf);
+    
+    /* configuration file */
+#ifdef PREFIXES_IN_USE
+    Sprintf(buf, " (in %s)",
+            fqn_prefix_names[CONFIGPREFIX]);
+#else /* PREFIXES_IN_USE */
+    buf[0] = '\0';
+#endif
+    raw_printf("Your personal configuration file%s:", buf);
+#ifdef UNIX
+    envp = nh_getenv("HOME");
+    if (!envp)
+        Strcpy(nhpath, ".nethackrc");
+    else
+        Sprintf(nhpath, "%s/%s", envp, default_configfile);
+#endif
+    raw_printf("    \"%s\"",
+#ifdef UNIX
+                nhpath);
+#else
+#ifdef PREFIXES_IN_USE
+                fqname(default_configfile, CONFIGPREFIX, 3));
+#else
+                default_configfile);
+#endif  /* PREFIXES_IN_USE */
+#endif  /* UNIX */
+    raw_print("");
+}
+
 /* ----------  BEGIN TRIBUTE ----------- */
 
 /* 3.6 tribute code