We have to ensure that the sysroot created while building the
toolchain will be the one we later search for libraries. So:
- hide the sysroot name prompt from the ct-ng menu.
- force the sysroot name to be 'sysroot'.
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>