Sublime tries absolute paths for pkexec/gksudo

[Mic92]

We are trying to package sublime merge for nixpkgs.
There we noticed that it tries to execute “/usr/bin/pkexec” and “/usr/bin/gksudo”.
Our package manager is build on the concept that every version/variant of a package
gets its own path below /nix/store/- to solve dependency hell and have roll-back support.
Usually packages are either wrapped to have all there runtime executables in their PATH variable
or we patch the source to replace the absolute paths with paths to our nix store at build.
However for sublime merge we cannot do both since it is closed-source.
Therefore it would be great if it ether do not use absolute paths for pkexec and gksudo or tries a non-absolute
version after it has executed the absolute one.

[jtojnar]

The package expression for reference: https://github.com/NixOS/nixpkgs/pull/47378/files