The problem (relating to the duplicate definition of TCP_NODELAY and TCP_MAXSEG) was "fixed" as a result of bug 1065. However, though the fix (changes to includes.h, one example being the section starting at line 312, another starting at line 371, and the last starting at 399) looks sane to me, there appears to be a problem with it. TCP_NODELAY does not get defined at all in my setup. I suspect the same is true of TCP_MAXSEG, but I don't know what that's used for, if anything. It looks like even though it is supposed to be getting defined 2x (and that is the reason for all of the #undef's), it seems to be getting #undef'd 2x also, instead of just once and then redefined. Since TCP_NODELAY is reported to be a performance enhancer, I certainly don't want to go without it (or at least, I don't /think/ I do).
See bug 2140 by Richard Allen.
*** This bug has been marked as a duplicate of 2140 ***