qscintilla: fix dylib names on Darwin
qscintilla: fix dylib names on Darwin

On Darwin dylibs are intended to have their install names set to their
absolute path. Without an absolute path, applications using these
libraries will have invalid references embedded, and will be unable to
locate the libraries at runtime.

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs