This is a followup to 48d498c2c3984784336b27ba5e261319f3ac6a3a, which introduced a typo (missing '->' in 'mlet'.) Fixes <https://bugs.gnu.org/35623>. Reported by Karrick McDermott <kmcdermott@linkedin.com>. * build-aux/build-self.scm (build): Add 'getenv' and 'setenv' calls for HOME.