This package maker project assumes that the product (which means XVim.xcplugin here) is at
build/release/XVim.xcplugin (relative to pmdoc)
Xcode default build setting make a product into somewhat specified by DrivedData dir which is not under XVim project directory. To make Xcode output a product into under "build" dir you have to specify the following setting from Xcode menu.
File - Project Settings -> "Advanced" in "Build" Tab -> Select "Locations Specified by Targets" for "Build Location"
Build XVim with "release" configuration make XVim plugin into the directory above.
Know better solution? Let me know please! ( I want to make XVim installer package automatically when build the project by Xcode )