$ cpp -A blabla </dev/null cpp: Internal error: Segmentation fault (program cpp0) Problem in gcc/cpplib.c, function do_assert, dereferencing null pointer. Bug still exists in current CVS tree. I'm not gcc hacker, so reporting here.
Actually, it seems this segfault went away in CVS with 2000-10-28 CPP lexer rewrite. As I don't trust that shiny new lever yet though, I wrote a fix for this for the old lexer and will be testing it with other changes in gcc-2.96-62.