portupgrade bugzilla fails with mysql > 4 installed

[Tim Kellers]

  The message while portupgrading bugzilla:

"bugzilla-3.6.2_1 depends on package: p5-DBD-mysql>=2.9003 - not found
Verifying reinstall for p5-DBD-mysql>=2.9003 in 
/usr/ports/databases/p5-DBD-mysql

p5-DBD-mysql-4.017 conflicts with installed package(s):
p5-DBD-mysql50-4.017

They install files into the same place.
Please remove them first with pkg_delete(1)"

The problem in Makefile:

".ifdef WITH_MYSQL
RUN_DEPENDS+=   p5-DBD-mysql>=2.9003:${PORTSDIR}/databases/p5-DBD-mysql
USE_MYSQL=      yes
IGNORE_WITH_MYSQL=      323
.endif"


For MySQL 5.0, I simply changed the references to p5-DBD-mysql to 
p5-DBD-mysql50 and the conflict was removed and portupgrade succeeded, 
but there must be a more thorough and elegant way.

Tim Kellers