Bugzilla Bug 74678

if an ebuild uses the builder style, the eclass should handle the DEPEND for
it:
if [[ ${style} = "builder" ]] ; then
    DEPEND="${DEPEND} dev-perl/module-build"
fi

also, if module-build isnt emerged, and you try to emerge a perl module which
needs it, the eclass doesnt fail at all:

root@spyro 0 ~ # emerge sdl-perl   
Calculating dependencies ...done!
>>> emerge (1 of 1) dev-perl/sdl-perl-2.1.2 to /
>>> md5 files   ;-) ChangeLog
>>> md5 files   ;-) metadata.xml
>>> md5 files   ;-) sdl-perl-1.20.3.ebuild
>>> md5 files   ;-) sdl-perl-2.1.2.ebuild
>>> md5 files   ;-) files/digest-sdl-perl-1.20.3
>>> md5 files   ;-) files/digest-sdl-perl-2.1.2
>>> md5 src_uri ;-) SDL_Perl-2.1.2.tar.gz
>>> Unpacking source...
>>> Unpacking SDL_Perl-2.1.2.tar.gz to /var/tmp/portage/sdl-perl-2.1.2/work
>>> Source unpacked.
Base class package "Module::Build" is empty.
    (Perhaps you need to 'use' the module which defines that package first.)
 at make/lib/SDL/Build.pm line 9
BEGIN failed--compilation aborted at make/lib/SDL/Build.pm line 9.
Compilation failed in require at
/var/tmp/portage/sdl-perl-2.1.2/work/SDL_Perl-2.1.2/Build.PL line 11.
BEGIN failed--compilation aborted at
/var/tmp/portage/sdl-perl-2.1.2/work/SDL_Perl-2.1.2/Build.PL line 11.
>>> Test phase [not enabled]: dev-perl/sdl-perl-2.1.2

*** Bug 74727 has been marked as a duplicate of this bug. ***

*** Bug 74736 has been marked as a duplicate of this bug. ***

*** Bug 74821 has been marked as a duplicate of this bug. ***

I got sidetracked in real life, but work for making module::build as a "core"
part of the eclass is already under way. Arch's have tested, and forthcoming is
a change to the eclass to handle Build.pl scripts internally.

*** Bug 75700 has been marked as a duplicate of this bug. ***

Smile - does now.