There is a big need in testers that have access to exotic platforms(zArch, MIPS) and compilers (Cray, IBM xlc ...).
it should be possible to use a cross-compiler and test via qemu if the hardware is not easy to access ... a few years ago i used such at toolchain in order to test altivec/neon code without having access to ppc or arm hardware ... it basically boils down to point the toolchain to the cross-compiler and to run the testsuite via qemu. this was pretty straight-forward with cmake though i'm not familiar enough with bjam to say it this can easily be integrated ... emdebian seems to provide quite binaries of cross-compilers for quite some architectures ... so maybe emulating exotic architectures is easier to achieve than getting access to the hardware cheers, tim