Don't restore sys.platform in venv.py (#108)

This is buggy when combined with pip 25. The commit when it was added
mentions it was needed for `test_oot_build` to pass, but it seems to
pass now.

Tested downstream:
pyodide/pyodide#5455

CHANGELOG.md

@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+### Fixed
+
+- Fixed Pyodide venv `sys_platform` marker evaluation with pip >= 25.
+  [#108](https://github.com/pyodide/pyodide-build/pull/108)
+
 ## [0.29.3] - 2025/02/04
 
 ### Added

pyodide_build/out_of_tree/venv.py

@@ -141,7 +141,6 @@ def platform_tags():
         f"""
         os_name, sys_platform, platform_system, multiarch, host_platform = {platform_data}
         os.name = os_name
-        orig_platform = sys.platform
         sys.platform = sys_platform
         sys.platlibdir = "lib"
         sys.implementation._multiarch = multiarch
@@ -153,7 +152,6 @@ def platform_tags():
         import sysconfig
         sysconfig._init_config_vars()
         del os.environ["_PYTHON_SYSCONFIGDATA_NAME"]
-        sys.platform = orig_platform
         """
     )