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 makeself-header.sh file, makeself by default expects it to be at the same location as the makeself.sh 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 $(which makeself))/../share/makeself/makeself-header.sh
Then when running makeself:
makeself --header "$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)?