i tried to put some things into the devel_0_38 but couldn't really get it to work, and so it stopped being fun after a while (devel_0_38 currently does not load externals, and i didn't want to find out why)
you're on linux ... i don't have any problems running my externals compiled for 37 (devel) under 38 (devel) ... using the (i know, deprecated) .pdrc file ...
cheers ... tim