It's easier to have as much as possible stuff in the same place to
ease backup/restore, and make things easier to follow.
Move the host companion libraries install dir as a sub-dir of the
build-tools install dir (but not directly in it, it would break
for canadian or cross-native).
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>