Hi, This is a bit rambling but I'm kind of stuck now.
I hadn't kept up to date with git master for a while. I ran into trouble with the windows makefiles (makefile.win32) - GTK was not defined even though -DGTK is passed. So I hacked PlatGTK.cxx to define it manually, but on running the resultant Geany aborts - a backtrace showed some Scintilla code (Document::Document) causing the fault. (I also had to remove -liberty as that doesn't seem to be part of my MinGW install).
Anyway, I gave up trying to fix the makefiles and tried Waf. It seemed to work, but now when using Geany autocompletion shows an empty list. It keeps doing this for a while on typing, then later I start typing again and Geany freezes - this is not a hang, task manager doesn't show Geany using CPU. I have to kill it. This is weird, and annoying because I don't know how to get a backtrace (Ctrl-Z doesn't seem to work on my Windows gdb, and anyway the process seems stuck rather than looping). I suspect a fault with Scintilla, but it could be unrelated.
I also noticed Waf doesn't seem to use -mms-bitfields, but I'm not certain.