Some of Linaro developers works with ARM devices older then ARMv7-a architecture. Other people experiments with hard-float ABI. Each of them has to rebuild toolchain for own use and that means playing with components to have them build properly.
But it is no more - I made some patches and armel-cross-toolchain-base since 1.53 version + newer source packages for gcc-4.-armel-cross have support for "debian/flavour" file which allows to set some flags related to toolchain build.
So far supported things are:
- ARM architecture - float ABI - FPU mode - Thumb mode
This feature is not merged into regular Ubuntu packages yet as this is work in progress which needs to be cleaned first.
http://people.linaro.org/~hrw/armel-cross-toolchain/ has all source packages needed.