Work-around problem in src/sbbs3/GNUmakefile:

Macros in sbbsdefs.mk should only be defined when building libsbbs.so. This is
the cause of the "static declaration of 'x' follows non-static declaration" GCC
warnings. While harmless warnings now, in GCC 3.5, this condition has been
elevated to a compile error. :-(
The real fix needs to be made in GNUmakefile someday (Deuce). :-)