- fix build against autoconf 2.67
+ update to desktop-file-utils 0.17:
- accept chemical/* mime types as valid types
- make icon names with an extension for Icon key a non-fatal
error
- check that a main category is included in the Categories
- check that categories required by another one are present
- do not always show warnings about KDE specific uses
- check that the Comment does not look like the Name and the
GenericName
- display error about multiple keys with the same name earlier
- improve MIME type check to make sure that the MIME types are
valid
- add LXDE in the list of registered OnlyShowIn values
- add "warning" to error strings to make them easily greppable
- handle AutostartCondition key, as proposed for the autostart
specification and used in GNOME
- accept empty Categories key as valid
- make new errors non-fatal to give some time to maintainers to
fix their .desktop file after a release of desktop-file-utils
- plug leak
- code cleanups