The original placement in installation root was developed for earlier
glib, and doesn't work for current mingw-w64-x86_64-glib2 2.58.1-1
(actually it breaked several versions ago). This prevents opening help
from meld, since this uses external process execution, like
GNOME/meld#197

Also looking at the previous code version I found that it had typo in
the comment describing return value format. It's fixed now.