Fixed Windows installer so installation folder not added to PATH multiple times.

Also, updated installer readme.txt and fix typo in licensing.

Author: nrsiward

installer/readme.txt

@@ -24,13 +24,13 @@ Documentation files ("doc" folder)
 
 INSTALLING THE PROGRAM
 
-Please uninstall any prior versions. After running the installer program, all the program files will be located in the indicated folder. The Path environment variable will be modified to include the directory containing grcompiler.exe.
+Please uninstall any prior versions (see below). After running the installer program, all the program files will be located in the indicated folder. The PATH environment variable will be modified to include the directory containing grcompiler.exe.
 
 If you choose to put the gdlpp.exe file in a different folder from GrCompiler.exe, you need to set the GDLPP environment variable to indicate where this utility is, for instance: "c:\graphite_extras\gdlpp.exe". Note that the variable must include the name of the program as well as well as the path. Also, the actual env var must be set without using quote marks.
 
 The GDLPP_PREFS environment variable is used to indicate where the Graphite compiler will find #included files. The value consists of "-I" followed by the path or paths to files of interest, for instance, "-Ic:\graphite" (without quotes marks in actual use). At the very least, you will want to be able to #include "stddef.gdh", which is the standard include file that contains all the standard GDL abbreviations. If it is located in a different folder than the GDL source code and font file, you will need to put its path in the GDLPP_PREFS environment variable. The installer will initialize GDLPP_PREFS to point to the directory containing this file, which will be in the same directory as grcompiler.exe.
 
-NOTE: GDLPP_PREFS must not contain directory names with spaces. If there are spaces in your path, you will need to use 8-character directory names. So if, for instance, your "stddef.gdh" file is located in C:\Program Files\Graphite Compiler, GDLPP_PREFS should be set to "-IC:\Progra~1\Graphi~1" (without quotes). If the compiler is having trouble finding the stddef.gdh file (ie, standard definitions are not recognized), check your GDLPP_PREFS environment variable and change it to use short names if necessary.
+NOTE: GDLPP_PREFS must not contain directory names with spaces. If there are spaces in your path, you will need to use 8-character directory names. So if, for instance, your "stddef.gdh" file is located in "C:\Program Files\Graphite Compiler", GDLPP_PREFS should likely be set to "-IC:\Progra~1\Graphi~1" (without quotes). If the compiler is having trouble finding the stddef.gdh file (ie, standard definitions are not recognized), check your GDLPP_PREFS environment variable and change it to use short names if necessary. (Alternatively, you can install the compiler into a folder with no spaces in its path or copy the "stddef.gdh" to the same folder as the GDL source code or specify the path to it in the #include directive.)
 
 
 RUNNING THE COMPILER
@@ -77,4 +77,4 @@ The file "allcaps.gdl" is a very simple program that you can try to compile whic
 
 UNINSTALLING THE PROGRAM
 
-To uninstall, run "unins000.exe".
+To uninstall, run "unins000.exe". You may also want to remove the installation folder from the PATH.

installer/windows/grcompiler.iss

@@ -56,8 +56,8 @@ Name: "{group}\Compiler Debug Files Doc"; Filename: "{app}\doc\CompilerDebugFile
 Name: "{commondesktop}\Graphite Compiler"; Filename: "{app}\GrCompiler.exe"; Tasks: desktopicon
 
 [Registry]
-Root: HKLM; Subkey: "SYSTEM\CurrentControlSet\Control\Session Manager\Environment"; ValueType: string; ValueName: "GDLPP_PREFS"; ValueData: "-I{code:GetShortName|{app}}"
-Root: HKLM; Subkey: "SYSTEM\CurrentControlSet\Control\Session Manager\Environment"; ValueType: expandsz; ValueName: "Path"; ValueData: "{olddata};{app}"; Check: NeedsAddPath('{app}')
+Root: HKLM; Subkey: "SYSTEM\CurrentControlSet\Control\Session Manager\Environment"; ValueType: string; ValueName: "GDLPP_PREFS"; ValueData: "-I{code:GetShortName|{app}}"; Flags: uninsdeletevalue
+Root: HKLM; Subkey: "SYSTEM\CurrentControlSet\Control\Session Manager\Environment"; ValueType: expandsz; ValueName: "Path"; ValueData: "{olddata};{app}"; Check: NeedsAddPath(ExpandConstant('{app}'))
 
 
 [Messages]
@@ -78,7 +78,8 @@ begin
   end;
 end;
 
-// This check does not seem to be working (as of 2/28/2012):
+// Check if install directory should be added to the PATH
+// see https://stackoverflow.com/questions/3304463/how-do-i-modify-the-path-environment-variable-when-running-an-inno-setup-install
 function NeedsAddPath(NewDir: string): boolean;
 var
   OrigPath: string;

license/LICENSING.txt

@@ -1,6 +1,6 @@
 Graphite Compiler Licensing
 ============================
-Copyright 1999-2021, SIL International  (http://ww.sil.org).
+Copyright 1999-2021, SIL International  (http://www.sil.org).
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of either: