build: Make sure precompiled libraries exists before copying elf.h
build: Make sure precompiled libraries exists before copying elf.h

mnordsletten/IncludeOS,AndreasAakesson/IncludeOS,AndreasAakesson/IncludeOS,hioa-cs/IncludeOS,AnnikaH/IncludeOS,AnnikaH/IncludeOS,mnordsletten/IncludeOS,AndreasAakesson/IncludeOS,AnnikaH/IncludeOS,alfred-bratterud/IncludeOS,hioa-cs/IncludeOS,alfred-bratterud/IncludeOS,AnnikaH/IncludeOS,AndreasAakesson/IncludeOS,AndreasAakesson/IncludeOS,mnordsletten/IncludeOS,hioa-cs/IncludeOS,AnnikaH/IncludeOS,AndreasAakesson/IncludeOS,hioa-cs/IncludeOS,alfred-bratterud/IncludeOS,alfred-bratterud/IncludeOS,hioa-cs/IncludeOS,mnordsletten/IncludeOS,mnordsletten/IncludeOS,mnordsletten/IncludeOS,alfred-bratterud/IncludeOS