Distribution/Version: 98

g_get_system_data_dirs() uses the special folders specified by
CSIDL_COMMON_APPDATA and CSIDL_COMMON_DOCUMENTS and g_get_system_config_dirs()
uses CSIDL_COMMON_APPDATA.

The above CSIDLs are not available prior to WindowsME/2000 (unless you are using
the ShFolder redistributable (in which which case you also need to link to
SHFolder.lib))

g_get_system_data_dirs() is used in gkeyfile.c and gtkicontheme.c; both cases
don't expect a NULL value to be returned and will consequently blow up.

This effectively makes most gtk apps (anything that uses a window with
decorations) unusable on Windows98.

I think it makes sense we should be able to assume that thse functions won't
return NULL, so I think that they should fall back to CSIDL_APPDATA.

I'll post a patch in a minute.