Even with a eprefixified dev-php5/pecl-imagick-3.0.1-r1 ebuild the compilation fails because of the php-ext-source eclass. I merged some of the changes of the prior version and it builds & runs now just fine.
Created attachment 286607 [details, diff] eprefixifed pecl-imagick ebuild (~x64-macos)
Created attachment 286609 [details, diff] eprefixified php-ext-source-v2.eclass
Ouch, what a fail, I should've search my own bugs first. -.- *** This bug has been marked as a duplicate of bug 358987 ***