Add file location to the translation files

Makes it easier for the translators to check context and report
problems.
diff --git a/po/CMakeLists.txt b/po/CMakeLists.txt
index 6d6f888..793089c 100644
--- a/po/CMakeLists.txt
+++ b/po/CMakeLists.txt
@@ -26,7 +26,7 @@
       "--copyright-holder=TigerVNC Team and many others \(see README.txt\)"
       --msgid-bugs-address=tigervnc-devel@googlegroups.com
       --sort-output
-      --no-location
+      --add-location
       ${po_source}
     COMMENT "Updating tigervnc.pot"
     VERBATIM