--- a/nsis/gvim.nsi
+++ b/nsis/gvim.nsi
@@ -1,6 +1,6 @@
 # NSIS file to create a self-installing exe for Vim.
 # It requires NSIS version 3.0 or later.
-# Last Change:	2024 Mar 17
+# Last Change:	2024 Mar 18
 
 Unicode true
 
@@ -17,7 +17,7 @@ Unicode true
   !define VIMRT ".."
 !endif
 
-# Location of extra tools: diff.exe
+# Location of extra tools: diff.exe, winpty{32|64}.dll, winpty-agent.exe, etc.
 !ifndef VIMTOOLS
   !define VIMTOOLS ..\..
 !endif
@@ -29,29 +29,40 @@ Unicode true
   !define GETTEXT ${VIMRT}
 !endif
 
-# Comment the next line if you don't have UPX.
-# Get it at https://upx.github.io/
-!define HAVE_UPX
+# If you have UPX, use the switch /DHAVE_UPX=1 on the command line makensis.exe.
+# This property will be set to 1. Get it at https://upx.github.io/
+!ifndef HAVE_UPX
+  !define HAVE_UPX 0
+!endif
+
+# If you do not want to add Native Language Support, use the switch /DHAVE_NLS=0
+# in the command line makensis.exe. This property will be set to 0.
+!ifndef HAVE_NLS
+  !define HAVE_NLS 1
+!endif
 
-# Comment the next line if you do not want to add Native Language Support
-!define HAVE_NLS
+# To create an English-only the installer, use the switch /DHAVE_MULTI_LANG=0 on
+# the command line makensis.exe. This property will be set to 0.
+!ifndef HAVE_MULTI_LANG
+  !define HAVE_MULTI_LANG 1
+!endif
 
-# Comment the following line to create an English-only installer:
-!define HAVE_MULTI_LANG
-
-# Uncomment the next line if you want to create a 64-bit installer.
-#!define WIN64
+# if you want to create a 64-bit the installer, use the switch /DWIN64=1 on
+# the command line makensis.exe. This property will be set to 1.
+!ifndef WIN64
+  !define WIN64 0
+!endif
 
 !include gvim_version.nsh	# for version number
 
-# Definition of Patch for Vim
+# Definition of Patch for Vim.
 !ifndef PATCHLEVEL
   !define PATCHLEVEL 0
 !endif
 
 # ----------- No configurable settings below this line -----------
 
-!include "Library.nsh"		# For DLL install
+!include "Library.nsh"		# for DLL install
 !include "LogicLib.nsh"
 !include "MUI2.nsh"
 !include "nsDialogs.nsh"
@@ -93,7 +104,7 @@ Unicode true
 !define UNINST_REG_KEY	"Software\Microsoft\Windows\CurrentVersion\Uninstall"
 !define UNINST_REG_KEY_VIM  "${UNINST_REG_KEY}\${PRODUCT}"
 
-!ifdef WIN64
+!if ${WIN64}
 Name "${PRODUCT} (x64)"
 !else
 Name "${PRODUCT}"
@@ -106,11 +117,11 @@ ManifestDPIAware true
 SetDatablockOptimize on
 RequestExecutionLevel highest
 
-!ifdef HAVE_UPX
+!if ${HAVE_UPX}
   !packhdr temp.dat "upx --best --compress-icons=1 temp.dat"
 !endif
 
-!ifdef WIN64
+!if ${WIN64}
 !define BIT	64
 !else
 !define BIT	32
@@ -150,7 +161,7 @@ RequestExecutionLevel highest
 
 # This adds '\Vim' to the user choice automagically.  The actual value is
 # obtained below with CheckOldVim.
-!ifdef WIN64
+!if ${WIN64}
   !define DEFAULT_INSTDIR "$PROGRAMFILES64\Vim"
 !else
   !define DEFAULT_INSTDIR "$PROGRAMFILES\Vim"
@@ -194,7 +205,7 @@ Page custom SetCustom ValidateCustom
 !include "lang\english.nsi"
 
 # Include support for other languages:
-!ifdef HAVE_MULTI_LANG
+!if ${HAVE_MULTI_LANG}
     !include "lang\danish.nsi"
     !include "lang\dutch.nsi"
     !include "lang\german.nsi"
@@ -598,7 +609,7 @@ SectionGroup $(str_group_plugin) id_grou
 SectionGroupEnd
 
 ##########################################################
-!ifdef HAVE_NLS
+!if ${HAVE_NLS}
 Section "$(str_section_nls)" id_section_nls
 	SectionIn 1 3
 
@@ -688,7 +699,7 @@ Section -post
 	  SectionGetSize ${id_section_editwith} $4
 	  IntOp $3 $3 + $4
 	${EndIf}
-!ifdef HAVE_NLS
+!if ${HAVE_NLS}
 	${If} ${SectionIsSelected} ${id_section_nls}
 	  SectionGetSize ${id_section_nls} $4
 	  IntOp $3 $3 + $4
@@ -718,7 +729,7 @@ Section -post
 	!insertmacro SaveSectionSelection ${id_section_vimrc}      "select_vimrc"
 	!insertmacro SaveSectionSelection ${id_section_pluginhome} "select_pluginhome"
 	!insertmacro SaveSectionSelection ${id_section_pluginvim}  "select_pluginvim"
-!ifdef HAVE_NLS
+!if ${HAVE_NLS}
 	!insertmacro SaveSectionSelection ${id_section_nls}        "select_nls"
 !endif
 	${If} ${RunningX64}
@@ -751,7 +762,7 @@ SectionEnd
 !macroend
 
 Function .onInit
-!ifdef HAVE_MULTI_LANG
+!if ${HAVE_MULTI_LANG}
   # Select a language (or read from the registry).
   !insertmacro MUI_LANGDLL_DISPLAY
 !endif
@@ -789,7 +800,7 @@ Function .onInit
   !insertmacro LoadSectionSelection ${id_section_vimrc}      "select_vimrc"
   !insertmacro LoadSectionSelection ${id_section_pluginhome} "select_pluginhome"
   !insertmacro LoadSectionSelection ${id_section_pluginvim}  "select_pluginvim"
-!ifdef HAVE_NLS
+!if ${HAVE_NLS}
   !insertmacro LoadSectionSelection ${id_section_nls}        "select_nls"
 !endif
   # Load the default _vimrc settings from the registry (if any).
@@ -963,7 +974,7 @@ FunctionEnd
     !insertmacro MUI_DESCRIPTION_TEXT ${id_group_plugin}        $(str_desc_plugin)
     !insertmacro MUI_DESCRIPTION_TEXT ${id_section_pluginhome}  $(str_desc_plugin_home)
     !insertmacro MUI_DESCRIPTION_TEXT ${id_section_pluginvim}   $(str_desc_plugin_vim)
-!ifdef HAVE_NLS
+!if ${HAVE_NLS}
     !insertmacro MUI_DESCRIPTION_TEXT ${id_section_nls}         $(str_desc_nls)
 !endif
 !insertmacro MUI_FUNCTION_DESCRIPTION_END
@@ -973,7 +984,7 @@ FunctionEnd
 # Uninstaller Functions and Sections
 
 Function un.onInit
-!ifdef HAVE_MULTI_LANG
+!if ${HAVE_MULTI_LANG}
   # Get the language from the registry.
   !insertmacro MUI_UNGETLANGUAGE
 !endif