gimme: Add GIMME_HOSTOS
gimme: Add GIMME_HOSTOS

For cross build support.

Signed-off-by: Geoff Levand <c3918f39022407dee6a0056ceca9b1aa80e8e4ce@infradead.org>

glevand/travis-ci--gimme,glevand/travis-ci--gimme,travis-ci/gimme,kofalt/gimme,travis-ci/gimme,meatballhat/gimme