If you have config with an implicit bool like:
[trace2]
envvars
we'll segfault, as we unconditionally try to xstrdup() the value. We
should instead detect and complain, as a boolean value has no meaning
here. The same is true for every variable in tr2_sysenv_settings (and
this patch covers them all, as we check them in a loop).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>