When Red Hat Enterprise Linux does not offer packages that we need, EPEL (Extra Packages for Enterprise Linux) often has what we want, kept compatible with RHEL. When EPEL also doesn't have a package, or we need a newer release than is offered, we rebuild packages from Fedora, which has consistently high-quality packages even in its "rawhide" development phase. We then distribute our packages in several compatibility-oriented Yum repositories at packages.endpoint.com.
Of course some things in the latest Fedora are not compatible with RHEL. In rebuilding the logcheck package (needed as a dependency for another package), I found that Fedora RPM spec files have begun using the _sharedstatedir macro in /usr/lib/rpm/macros, which RHEL has never used before.
On RHEL that macro has been set to /usr/com, a strange nonexistent path that apparently came from the GNU autoconf tools but wasn't used in RHEL. Now in Fedora the macro is set to /var/lib and is being used, as described in a Fedora wiki page on packaging.
The easiest and most compatible way to make the change without munging the system- or user-wide RPM macros is to add this definition to the top of the spec file where it's needed:
%define _sharedstatedir /var/lib
And then the RPM build is happy.
In related news, alongside the new logcheck package, there are also new End Point RHEL 5 x86_64 packages for the brand-new Git 126.96.36.199 and pbzip2 1.1.5, the multi-CPU core parallel compressor that has had several bugfix releases this year.