When I reached out to vrthra / Rahul Gopinath about this PR, he
indicated that he no longer has the time to serve as tcl maintainer
and suggested that I take on the responsibility.
Implement tclPackageHook, a setup hook that adjusts TCLLIBPATH to include the
paths of any installed Tcl packages, propagates that TCLLIBPATH to
anti-dependencies, and wraps any installed binaries to set their TCLLIBPATH.
Additionally, implement a makePythonPackage-style mkDerivation wrapper to use
reasonable defaults for Tcl packages and use tclPackageHook.
He prefers to contribute to his own nixpkgs fork triton.
Since he is still marked as maintainer in many packages
this leaves the wrong impression he still maintains those.
This cuts about 3 MiB from the installed size. On Linux, the configure
script is supposed to detect that installing tzdata is unnecessary,
but it looks in locations like /usr/share/zoneinfo.
This reduces tcl's total size from 25.0 MiB to 8.6 MiB. Admittedly
this is also because putting the manpages in the right place causes
all man3 pages to be deleted by the multiple outputs setup hook. Not
sure if that's desirable behaviour...
