I just more or less successfully compiled emacs-24.2 for a Samsung Chromebook. I did it by using the chrooted build environment for chromiumos. In the process I learned a couple of things.
I used the configuration:
../emacs-24.2/configure --build=x86_64-pc-linux-gnu --host=arm-none-linux-gnueabi --target=arm-none-linux-gnueabi --with-x-toolkit=no --with-xpm=no --with-jpeg=no --with-png=no --with-gif=no --with-tiff=no --without-xml2 --without-gnutls --without-x --without-dbus --with-crt-dir=/build/arm-generic/usr/lib/
Obviously, I also had to CANNOT_DUMP=yes as well.
1) It doesn't look like emacs has a concept of a BUILDCC. I like to set CC to the cross compiler since that seems to be what most things need. However make-docfile and test-distrib need to be built with the local compiler. Usually the path to the local compiler is stored in BUILDCC. I just changed the $(CC) to $(BUILDCC) in the makefile for those two file and everything compiled ok.
2) The lisp and leim directories really want a local copy of emacs to compile. Since I didn't have one available in the chrooted environment, I just used /bin/true. Suboptimal, but it let the compile complete. I didn't see an obvious way to set the path to an external emacs, I just edited the makefile.