It's probably safe to say that there are not many Gentoo Linux users out there who are actively developing WinCE applications. However, today I compiled my first "Hello, WinCE World!" app, messagebox and all, using the compiler from the CeGCC project. CeGCC-0.51.0 is based on fairly recent tools (e.g. gcc-4.1.0), which is a big bonus.
Although seeing a "Hello, World!" dialog in Windows CE surely made my day, the CeGCC compiler is really only a means to get Linux running on a certain unnameable portable computing device for work. I'm using the HaRET bootloader which has shown promise for many others who have ported Linux to mobile or embedded devices that run WinCE.
Just in case there are any Gentoo users out there who would also like to install the compiler using Portage, I have included Ebuilds for CeGCC and MingW32CE that install the i686/Linux toolchain components. Just to clarify, for those who are compiling applications for Win32, or people who want to hack HaRET, use the MingW32CE toolchain. For those who are interested in porting GNU software to ARM/Win32, use CeGCC.
You can download the overlay in tarball format here, but I would suggest using layman, just like for my other overlays.
The ultimate goal of my current project is to have an industrial handheld compuer / scanner that runs Android, and so far its been coming along very well.