For the dependency chain A->B->B the old code created:
_PKGSRC_DEPS=", B-1.0, A-1.0", which obviously can't match the PKGNAME
of B.
Skip the _flavor-bootstrap-depends processing if PKG_FAIL_REASON is
already set and move the check for circular dependencies right after the
block that defines PKGNAME and friends.
4be66048ad