I have currently used the standalone toolchain from Android's NDK, but it seems rather difficult to cross compile programs because the libraries provided in NDK lack a lot of things.
I've built binutils using NDK standalone toolchain and it all compiled (although I haven't tested to see if the binaries really work), but when it came to GCC it became rather difficult.
I saw a toolchain and sysroot downloadable from Gnash's website, but when I tried to run it on my computer it didn't work because the package was simply packaged from its original environment has very poor portability.
I'm wondering if there are other prebuilt GNU toolchains available for building thinsg on Android?
The only other option I know about is the Crystax NDK. Crystax adds some nice stuff like wide character support. I used Crystax in the early days and didn't have much luck. It is worth a try.