Add flag to disable PYTHONNOUSERSITE for wrapped python binaries

pkgs/development/interpreters/python/mk-python-derivation.nix

@@ -46,6 +46,9 @@
 # Skip wrapping of python programs altogether
 , dontWrapPythonPrograms ? false
 
+# Skip setting the PYTHONNOUSERSITE environment variable in wrapped programs
+, skipNoUserSite ? false
+
 # Remove bytecode from bin folder.
 # When a Python script has the extension `.py`, bytecode is generated
 # Typically, executables in bin have no extension, so no bytecode is generated.
@@ -93,6 +96,7 @@ let self = toPythonModule (python.stdenv.mkDerivation (builtins.removeAttrs attr
   installCheckInputs = checkInputs;
 
   postFixup = lib.optionalString (!dontWrapPythonPrograms) ''
+    ${if skipNoUserSite then "export SKIPNOUSERSITE=1" else ""}
     wrapPythonPrograms
   '' + lib.optionalString removeBinBytecode ''
     if [ -d "$out/bin" ]; then

pkgs/development/interpreters/python/wrap.sh

@@ -73,9 +73,12 @@ wrapPythonProgramsIn() {
                     # (see pkgs/build-support/setup-hooks/make-wrapper.sh)
                     local -a wrap_args=("$f"
                                     --prefix PATH ':' "$program_PATH"
-                                    --set PYTHONNOUSERSITE "true"
                                     )
 
+                    if [ -z "$SKIPNOUSERSITE" ]; then
+                        wrap_args+=(--set PYTHONNOUSERSITE "true")
+                    fi
+
                     # Add any additional arguments provided by makeWrapperArgs
                     # argument to buildPythonPackage.
                     local -a user_args="($makeWrapperArgs)"