Remove unwanted metadata from SVG files. (Closes: #956102)

Makefile

@@ -39,6 +39,12 @@ build-logos clean-logos install-logos:
 install: install-grub install-emblems install-logos install-local
 
 install-local:
+	# Ensure SVG files don’t include inkscape:export-filename. (See #956102)
+	if find . -name "*.svg" -exec grep inkscape:export-filename {} + ; then \
+		echo "error: please remove inkscape:export-filename attribute from SVGs, it tends to leak information about the user who did the export."; \
+		exit 1; \
+	fi
+
 	# debian logo in circle as default user face icon
 	install -d $(DESTDIR)/etc/skel
 	$(INSTALL_DATA) defaults/common/etc/skel/.face $(DESTDIR)/etc/skel
@@ -54,6 +60,7 @@ install-local:
 	mkdir -p $(DESTDIR)/usr/share/pixmaps
 	$(INSTALL_DATA) $(PIXMAPS) $(DESTDIR)/usr/share/pixmaps/
 
+
 	# Create a 'debian-theme' symlink in plymouth themes folder, pointing at the
 	# plymouth theme for the currently active 'desktop-theme' alternative.
 	mkdir -p $(DESTDIR)/usr/share/plymouth/themes