The C version of path_id does not look at the environment anymore, so
there is no reason to empty it.
ENV{ID_SERIAL}=="?*", ENV{ID_IFACE}=="?*", ENV{ID_ID}="$env{ID_BUS}-$env{ID_SERIAL}-$env{ID_IFACE}"
ENV{ID_SERIAL}=="?*", ENV{ID_IFACE}=="", ENV{ID_ID}="$env{ID_BUS}-$env{ID_SERIAL}"
-ENV{ID_PATH}=="", IMPORT{program}="/usr/bin/env -i /lib/udev/path_id %p/controlC%n"
+ENV{ID_PATH}=="", IMPORT{program}="path_id %p/controlC%n"
# The values used here for $SOUND_FORM_FACTOR and $SOUND_CLASS should be kept
# in sync with those defined for PulseAudio's src/pulse/proplist.h