build-sys: program_invocation_short_name is defined in errno.h

Copy fix from buildroot.

Address: http://git.buildroot.net/buildroot/tree/package/util-linux/util-linux-003-program-invocation-short-name.patch
Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Sami Kerola <kerolasa@iki.fi>