From the old Equi4 Software site wiki
A Starpack is a special version of a Starkit, which combines a Starkit with a Tclkit runtime into a single file. See single-file starpacks.
Assembling a starpack is simple:
sdx wrap hello.exe -runtime tclkit-win32.upx.exe
There is one caveat: do not specify the same tclkit file as the one which is used to run sdx (create a copy, this is a temporary restriction).
As you can see in the above example, starpacks for any platform can be built on any platform.