package/pseudo: enforce the host bitness

pseudo can detect the host bitness, but is not sure about it: it checks
what type of file /bin/sh is, using file(1).

However, in some conditions, /bin/sh can be of a different bitness than
the rest of the system (weird, but not impossible), which causes build
issues.

Just enforce the bitness, so that pseudo needs not (wrongly) guess it.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Gaël PORTAY <gael.portay@savoirfairelinux.com>
Cc: Patrick Keroulas <patrick.keroulas@savoirfairelinux.com>
Cc: Erico Nunes <nunes.erico@gmail.com>
Cc: Julien BOIBESSOT <julien.boibessot@free.fr>
Cc: Arnout Vandecappelle <arnout@mind.be>
Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>