looks like tox prefers to have it in the host environment.
@@ -1,6 +1,7 @@
setuptools==67.3.3
setuptools-scm==7.1.0
pip==23.0.1
+wheel==0.40.0
virtualenv==20.19.0
pkgconfig==1.5.5
tox==4.0.19
setuptools >=45, !=60.6.0, !=60.7.0
setuptools_scm
pip
+wheel
virtualenv
pkgconfig
tox