diff --git a/fltk-options/Makefile b/fltk-options/Makefile
index 06b3b710b..c860bad4d 100644
--- a/fltk-options/Makefile
+++ b/fltk-options/Makefile
@@ -1,7 +1,7 @@
 #
 # fltk-options Makefile for the Fast Light Tool Kit (FLTK).
 #
-# Copyright 2023 by Bill Spitzak and others.
+# Copyright 2023-2024 by Bill Spitzak and others.
 #
 # This library is free software. Distribution and use rights are outlined in
 # the file "COPYING" which should have been included with this file.  If this
@@ -55,39 +55,39 @@ include makedepend
 
 install: all
 	echo "Installing fltk-options in $(DESTDIR)$(bindir)..."
-	-$(INSTALL_DIR) $(DESTDIR)$(bindir)
-	$(INSTALL_BIN) $(FLTK_OPTIONS) $(DESTDIR)$(bindir)/fltk-options$(EXEEXT)
+	-$(INSTALL_DIR) "$(DESTDIR)$(bindir)"
+	$(INSTALL_BIN) $(FLTK_OPTIONS) "$(DESTDIR)$(bindir)/fltk-options$(EXEEXT)"
 
 install-linux:
-	-$(INSTALL_DIR) $(DESTDIR)/usr/share/applications
-	$(INSTALL_DATA) fltk-options.desktop  $(DESTDIR)/usr/share/applications
+	-$(INSTALL_DIR) "$(DESTDIR)/usr/share/applications"
+	$(INSTALL_DATA) fltk-options.desktop "$(DESTDIR)/usr/share/applications"
 	for size in 16 32 48 64 128; do \
-		if test ! -d $(DESTDIR)/usr/share/icons/hicolor/$${size}x$${size}/apps; then \
-			$(INSTALL_DIR) $(DESTDIR)/usr/share/icons/hicolor/$${size}x$${size}/apps; \
+		if test ! -d "$(DESTDIR)/usr/share/icons/hicolor/$${size}x$${size}/apps"; then \
+			$(INSTALL_DIR) "$(DESTDIR)/usr/share/icons/hicolor/$${size}x$${size}/apps"; \
 		fi; \
-		$(INSTALL_DATA) icons/fltk-options-$$size.png $(DESTDIR)/usr/share/icons/hicolor/$${size}x$${size}/apps/fltk-options.png; \
+		$(INSTALL_DATA) icons/fltk-options-$$size.png "$(DESTDIR)/usr/share/icons/hicolor/$${size}x$${size}/apps/fltk-options.png"; \
 	done
-	-$(INSTALL_DIR) $(DESTDIR)/usr/share/mimelnk/application
-	$(INSTALL_DATA) x-fltk-options.desktop  $(DESTDIR)/usr/share/mimelnk/application
+	-$(INSTALL_DIR) "$(DESTDIR)/usr/share/mimelnk/application"
+	$(INSTALL_DATA) x-fltk-options.desktop "$(DESTDIR)/usr/share/mimelnk/application"
 
 install-osx:
 	echo Installing fltk-options in $(DESTDIR)/Applications...
-	-$(INSTALL_DIR) $(DESTDIR)/Applications/fltk-options.app
-	-$(INSTALL_DIR) $(DESTDIR)/Applications/fltk-options.app/Contents
-	$(INSTALL_DATA) fltk-options.app/Contents/Info.plist $(DESTDIR)/Applications/fltk-options.app/Contents/Info.plist
-	-$(INSTALL_DIR) $(DESTDIR)/Applications/fltk-options.app/Contents/MacOS
-	$(RM) $(DESTDIR)/Applications/fltk-options.app/Contents/MacOS/fltk-options
-	$(LN) $(bindir)/fltk-options $(DESTDIR)/Applications/fltk-options.app/Contents/MacOS/fltk-options
-	-$(INSTALL_DIR) $(DESTDIR)/Applications/fltk-options.app/Contents/Resources
-	$(INSTALL_DATA) fltk-options.app/Contents/Resources/fltk-options.icns $(DESTDIR)/Applications/fltk-options.app/Contents/Resources
+	-$(INSTALL_DIR) "$(DESTDIR)/Applications/fltk-options.app"
+	-$(INSTALL_DIR) "$(DESTDIR)/Applications/fltk-options.app/Contents"
+	$(INSTALL_DATA) fltk-options.app/Contents/Info.plist "$(DESTDIR)/Applications/fltk-options.app/Contents/Info.plist"
+	-$(INSTALL_DIR) "$(DESTDIR)/Applications/fltk-options.app/Contents/MacOS"
+	$(RM) "$(DESTDIR)/Applications/fltk-options.app/Contents/MacOS/fltk-options"
+	$(LN) $(bindir)/fltk-options "$(DESTDIR)/Applications/fltk-options.app/Contents/MacOS/fltk-options"
+	-$(INSTALL_DIR) "$(DESTDIR)/Applications/fltk-options.app/Contents/Resources"
+	$(INSTALL_DATA) fltk-options.app/Contents/Resources/fltk-options.icns "$(DESTDIR)/Applications/fltk-options.app/Contents/Resources"
 
 uninstall:
-	$(RM) $(DESTDIR)$(bindir)/fltk-options$(EXEEXT)
+	$(RM) "$(DESTDIR)$(bindir)/fltk-options$(EXEEXT)"
 
 uninstall-linux:
-	$(RM) $(DESTDIR)/usr/share/applications/fltk-options.desktop
-	$(RM) $(DESTDIR)/usr/share/icons/hicolor/*/fltk-options.png
-	$(RM) $(DESTDIR)/usr/share/mimelnk/application/x-fltk-options.desktop
+	$(RM) "$(DESTDIR)/usr/share/applications/fltk-options.desktop"
+	$(RM) "$(DESTDIR)/usr/share/icons/hicolor/*/fltk-options.png"
+	$(RM) "$(DESTDIR)/usr/share/mimelnk/application/x-fltk-options.desktop"
 
 uninstall-osx:
-	$(RM) -r $(DESTDIR)/Applications/fltk-options.app
+	$(RM) -r "$(DESTDIR)/Applications/fltk-options.app"