Parse error in percona-server.spec (RHEL5)

percona-server.spec contains code that CentOS 5 rpmbuild(1) considers a parse error (output below). As a result it's not possible to build PS RPM's in CentOS 5. Relevant code:

Provides: mysql-server
#
%if %{rhel}
BuildRequires: pam-devel
%endif
#
BuildRequires: %{distro_buildreq}

This was introduced in revno 419. BuildRequires need to be consolidated.

$ sh ~/percona-server/build/build-rpm.sh --nosign --quiet work/
rm -rf Percona-Server-5.5.28-rel29.3-release Percona-Server-5.5.28-rel29.3-debug
Prepare Percona Server sources
rm -rf Percona-Server-5.5.28-rel29.3 Percona-Server-5.5.28
ln -s Percona-Server Percona-Server-5.5.28-rel29.3
ln -s Percona-Server Percona-Server-5.5.28
cp -R HandlerSocket-Plugin-for-MySQL Percona-Server-5.5.28-rel29.3/storage
patch -p1 -d Percona-Server-5.5.28-rel29.3/storage < handlersocket.patch
patching file HandlerSocket-Plugin-for-MySQL/configure.ac
cp -R UDF "Percona-Server-5.5.28-rel29.3"
cd "Percona-Server-5.5.28-rel29.3"/UDF && autoreconf --install
Using `AC_PROG_RANLIB' is rendered obsolete by `AC_PROG_LIBTOOL'
libtoolize: `config.guess' exists: use `--force' to overwrite
libtoolize: `config.sub' exists: use `--force' to overwrite
libtoolize: `ltmain.sh' exists: use `--force' to overwrite
Installing license files
install -m 644 COPYING.* Percona-Server-5.5.28-rel29.3

Percona Server source code is ready
Now change directory to Percona-Server-5.5.28-rel29.3 define variables as show below

export CFLAGS="-O2 -g -fmessage-length=0 -D_FORTIFY_SOURCE=2"
export CXXFLAGS="-O2 -g -fmessage-length=0 -D_FORTIFY_SOURCE=2"
export LIBS=-lrt

and run cmake . -DCMAKE_BUILD_TYPE=RelWithDebInfo -DBUILD_CONFIG=mysql_release -DFEATURE_SET=community -DWITH_EMBEDDED_SERVER=OFF && make all install

error: parse error in expression
error: /home/buildbot/percona-server/build/percona-server.spec:236: parseExpressionBoolean returns -1
error: Package has no %description: Percona-Server-55