Make the script fail on unsupported platforms.

The old behavior was to fall back to linux related
routines. But since those will most certainly have
failed as well, this new behavior is probably better.
This change mostly concerns BSD or Solaris users, which
are not officially supported by the Shadowrun games anyway.

shadow_tune.pl

@@ -17,7 +17,7 @@ sub find_game_resources {
 
     $op_params->{edition} =~ s/Hongkong/Hong\ Kong/;
 
-    PATH_TRIAL: foreach my $path_expr (@{$op_params->{install_dirs}{$op_params->{platform}}}) {
+    PATH_TRIAL: foreach my $path_expr (@{$op_params->{install_dirs}{$^O}}) {
 
         foreach my $path (bsd_glob("$path_expr")) {
 
@@ -255,14 +255,14 @@ sub help_dialogue {
 
 		            ],                
 
-                   windows => [
+                   MSWin32 => [
 
 	                 "c:/Program Files{, (x86)}/{,Steam/steamapps/common/}Shadowrun*",
 		         "c:/GOG Games/Shadowrun*"
 
 		              ],
 
-                   mac => [ 
+                   darwin => [ 
 
 		         "~/Library/Application Support/Steam/SteamApps/common/Shadowrun*"
 
@@ -288,12 +288,10 @@ sub help_dialogue {
 
    #We try to determine the OS by checking what platform the Perl
    #implementation was compiled for. Linux is the fallback value.
-   if ($^O eq 'MSWin32') { $op_params{platform} = "windows"; }
-
-   elsif ($^O eq 'darwin') { $op_params{platform} = "mac"; }
-
-   else { $op_params{platform} = "linux"; }
-
+   die "This platform seems to be unsupported.\n" unless 
+   $^O eq 'MSWin32' ||
+   $^O eq 'darwin' ||
+   $^O eq 'linux'; 	   
 
    until (@ARGV == 0) {
 
@@ -311,7 +309,7 @@ sub help_dialogue {
                                    get_option();
                                    chomp($ARGV[0]); 
 				   $ARGV[0] =~ s/\/$//;
-				   unshift(@{$op_params{install_dirs}{$op_params{platform}}}, $ARGV[0]); 
+				   unshift(@{$op_params{install_dirs}{$^O}}, $ARGV[0]); 
 				 }
 
        elsif ($ARGV[0] =~ /-e/i) { get_option(); chomp($op_params{edition} = "\L$ARGV[0]"); }