Since I’m a long user of Xchat I decided to upgrade it and found that it does not compile with the recent glib library.
The problem is that the new versions of the glib library introduced one limitation for includes. Now you only have to include glib.h and every more specific inclusion breaks the builds.
Even thou I recently switched to HexChat I made a patch for Xchat 2.8.8, so it can compile with the newer glib version.
The patch is available here.