Makeself in nix-shell and header script in non-usable location

In a nix-shell I use makeself to create a self extracting installer.
#! nix-shell -p bash makeself
It fails with that it cannot find the file, makeself by default expects it to be at the same location as the script itself (in this case under “bin”).
A somewhat ugly workaround is to provide the path by going relative to the bin folder back up to share, and override the default location of the header script:
MAKESELF_HEADER=$(dirname $(which makeself))/../share/makeself/
Then when running makeself:
makeself --header "$MAKESELF_HEADER"...

Should this be fixed in the nix makeself installation itself, or is there a better way?
If no better way, should I report a bug at (github I believe it is)?