python3Packages.mkPythonMetaPackage: init

This function exists create a meta package containing [metadata files](https://packaging.python.org/en/latest/specifications/recording-installed-packages/) to satisfy a dependency on a package, without it actually having been installed into the environment.

pkgs/development/interpreters/python/python-packages-base.nix

@@ -61,6 +61,8 @@ let
 
   removePythonPrefix = lib.removePrefix namePrefix;
 
+  mkPythonMetaPackage = callPackage ./meta-package.nix { };
+
   # Convert derivation to a Python module.
   toPythonModule = drv:
     drv.overrideAttrs( oldAttrs: {
@@ -97,6 +99,7 @@ in {
   inherit buildPythonPackage buildPythonApplication;
   inherit hasPythonModule requiredPythonModules makePythonPath disabled disabledIf;
   inherit toPythonModule toPythonApplication;
+  inherit mkPythonMetaPackage;
 
   python = toPythonModule python;