Log Message:
Hack around configure/build problem on Digital Unix by adding
-D_SOCKADDR_LEN to CFLAGS.OSF1. DU has system headers that sometimes
provide the 4.4BSD length field and sometimes not, depending on which
_FOO_SOURCE things you define and other factors. The package's
configure script isn't coping; it's not fully clear why but it looks
like it's using different CFLAGS for configure tests and building, or
something like that...

PR 42474.