This macro was removed from the default RPM macro file. Interestly,
some of the arch specific macro's add it back it based on your distro
but it should not be counted on. However, __id still exists and its
command line args have historically been fairly stable so we will
directly use %{__id} -un to get the user name.
Supported and tested distros now include SLES10, SLES11, Chaos 4.x,
RHEL5, and Fedora 11. This update was mainly to address rebuildable
kernel module rpms, and correct rpm dependencies for each distro.
Brian Behlendorf