gen_buildnum_h_helper.cmd: fix for when CrissCross isn't the main project
gen_buildnum_h_helper.cmd: fix for when CrissCross isn't the main project

Signed-off-by: Steven Noonan <4068f0880b399410602d694b3cc711c8a8f4727e@uplinklabs.net>

prophile/crisscross,prophile/crisscross,prophile/crisscross,tycho/crisscross,tycho/crisscross,tycho/crisscross