This package uses variables banned in some scopes. This may stop working in future versions of Portage.
$ pkgcheck scan -k VariableScope mail-filter/spamassassin
VariableScope: version 3.4.5-r1: variable 'D' used in 'src_configure', line 139
VariableScope: version 3.4.6-r1: variable 'D' used in 'src_configure', line 139
Not sure how to address this. See  for details/background.
Seems like this is endemic to traditional Perl build systems.
I'm just going to watch bug #778806 and bug #836052, and follow their lead whenever (if ever) they act upon this issue.