Solaris includes "sys/stream.h" inside their "sys/socket.h".  This
include file adds many non-reserved macros to Mutt's namespace, two of
which conflict with existing Mutt macros.

The simplest fix would be to rename those macros in Mutt, however this
will cause difficulty with out-of-tree patches.  This fix creates a
wrapper include file that preserves those existing macros and prevents
the Solaris values from entering Mutt's namespace.