--- a/im/Makefile.in
+++ b/im/Makefile.in
@@ -7,14 +7,14 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
 
 include $(topsrcdir)/config/config.mk
 
 include $(topsrcdir)/config/rules.mk
 
-ifeq ($(OS_ARCH),WINNT)
+ifdef MAKENSISU
 # For Windows build the uninstaller during the application build since the
 # uninstaller is included with the application for mar file generation.
 libs::
 	$(MAKE) -C installer/windows uninstaller
 endif

--- a/im/installer/package-manifest.in
+++ b/im/installer/package-manifest.in
@@ -47,17 +47,17 @@
 
 [@AB_CD@]
 @RESPATH@/chrome/@AB_CD@@JAREXT@
 @RESPATH@/chrome/@AB_CD@.manifest
 @RESPATH@/@PREF_DIR@/all-l10n.js
 @RESPATH@/searchplugins/*
 @RESPATH@/dictionaries/*
 @RESPATH@/hyphenation/*
-#ifdef XP_WIN32
+#ifdef MAKENSISU
 @BINPATH@/uninstall/helper.exe
 #endif
 #ifdef MOZ_UPDATER
 @RESPATH@/update.locale
 @RESPATH@/updater.ini
 #endif
 
 [xpcom]

--- a/im/moz.build
+++ b/im/moz.build
@@ -11,11 +11,11 @@ DIRS += [
     'themes',
     'modules',
     'components'
 ]
 
 # app is always last as it packages up the built files on mac.
 DIRS += ['app']
 
-if CONFIG['OS_ARCH'] == 'WINNT':
+if CONFIG['MAKENSISU']:
     DIRS += ['installer/windows']
 

--- a/mail/Makefile.in
+++ b/mail/Makefile.in
@@ -18,17 +18,17 @@ check-sync-dirs::
 	@$(PYTHON) $(topsrcdir)/mail/check-sync-dirs.py \
 	   $(srcdir)/config/tooltool-manifests $(MOZILLA_SRCDIR)/browser/config/tooltool-manifests
 
 check:: check-sync-dirs
 endif
 
 include $(topsrcdir)/config/rules.mk
 
-ifeq ($(OS_ARCH),WINNT)
+ifdef MAKENSISU
 # For Windows build the uninstaller during the application build since the
 # uninstaller is included with the application for mar file generation.
 libs::
 	$(MAKE) -C installer/windows uninstaller
 ifdef MOZ_MAINTENANCE_SERVICE
 	$(MAKE) -C installer/windows maintenanceservice_installer
 endif
 endif

--- a/mail/installer/package-manifest.in
+++ b/mail/installer/package-manifest.in
@@ -48,17 +48,17 @@
 
 [@AB_CD@]
 @RESPATH@/chrome/@AB_CD@@JAREXT@
 @RESPATH@/chrome/@AB_CD@.manifest
 @RESPATH@/@PREF_DIR@/all-l10n.js
 @RESPATH@/searchplugins/*
 @RESPATH@/dictionaries/*
 @RESPATH@/hyphenation/*
-#ifdef XP_WIN32
+#ifdef MAKENSISU
 @BINPATH@/uninstall/helper.exe
 #endif
 #ifdef MOZ_UPDATER
 @RESPATH@/update.locale
 @RESPATH@/updater.ini
 #endif
 
 [xpcom]

--- a/mail/moz.build
+++ b/mail/moz.build
@@ -15,13 +15,13 @@ DIRS += [
     'jquery',
     'app',
 ]
 
 # Add components for external linkage build
 if CONFIG['MOZ_INCOMPLETE_EXTERNAL_LINKAGE']:
     DIRS += ['components']
 
-if CONFIG['OS_ARCH'] == 'WINNT':
+if CONFIG['MAKENSISU']:
     DIRS += ['installer/windows']
 
 TEST_DIRS += ['test/mozmill']
 

--- a/suite/Makefile.in
+++ b/suite/Makefile.in
@@ -7,14 +7,14 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
 
 include $(DEPTH)/config/autoconf.mk
 
 include $(topsrcdir)/config/rules.mk
 
-ifeq ($(OS_ARCH),WINNT)
+ifdef MAKENSISU
 # For Windows build the uninstaller during the application build since the
 # uninstaller is included with the application for mar file generation.
 libs::
 	$(MAKE) -C installer/windows uninstaller
 endif

--- a/suite/installer/package-manifest.in
+++ b/suite/installer/package-manifest.in
@@ -49,17 +49,17 @@
 @RESPATH@/defaults/profile/bookmarks.html
 @RESPATH@/defaults/profile/chrome/*
 @RESPATH@/defaults/profile/mimeTypes.rdf
 @RESPATH@/defaults/profile/panels.rdf
 @RESPATH@/dictionaries/*
 @RESPATH@/hyphenation/*
 @RESPATH@/@PREF_DIR@/suite-l10n.js
 @RESPATH@/searchplugins/*
-#ifdef XP_WIN32
+#ifdef MAKENSISU
 @BINPATH@/uninstall/helper.exe
 #endif
 #ifdef MOZ_UPDATER
 @RESPATH@/update.locale
 @RESPATH@/updater.ini
 #endif
 
 [xpcom]

--- a/suite/moz.build
+++ b/suite/moz.build
@@ -21,17 +21,17 @@ DIRS += [
     'themes/modern',
     'profile',
     'security',
     'shell/public',
     'shell/src',
     'smile',
 ]
 
-if CONFIG['OS_ARCH'] == 'WINNT':
+if CONFIG['MAKENSISU']:
     DIRS += ['installer/windows']
 
 # app is always last as it packages up the built files on mac.
 DIRS += [
     'build',
     'app',
 ]