Currently at McGimp 2.10.8 Standard Edition (2019).
Does not include the resynthesizer plugin itself but has recent builds against which building the plugin itself is a bit easier. The 'some plugins already included approach: download a binary from Partha, Photography and Related Musings. On Sourceforge the version recommended by Resynthesizer Gimp on OSX Gimp-2.8.18p1-Sierra.dmg ) (Original website no longer active as of May 2019. Currently the latest version is 2.8.12 built for Sierra. Sadly development seems to have stopped about a year ago. The batteries included approach, as recommended b resynthesizer: download a build from GIMP on OS X. 'Easy' as in 'still a pain', just like the other, third and fourth option. There are currently two relatively easy ways to get to this plugin.