Revert "Still not quite right..."

This reverts commit 2b590ca240285fdcc3fa78da9ac8eb7badd2b5e2.
Revert "Fix for install script environments"

This reverts commit c73c8e116d660ac33b6c1cedd9ef3daad25aff01.
Revert "Make install scripts run in login shell"

This reverts commit 6c311a54e79a8b65e0c9a284f6b73d4cd82ba832.