Abort on line numbering or column numbering overflow. Line numbers are limited to values that fit in "unsigned int". Also reject input lines longer than 2^32-1 characters. It seems reasonable to presume that any input that violates these constraints is someone screwing around and not a serious attempt to compile or preprocess anything useful. Done in response to n2129, but without getting into any of the silliness found there.

#define BC //**/*
#define EC */**//

BC
comment?
EC

BC comment? EC

#define FOO(x) x
FOO(abc BC def EC ghi)

#define BAR(x, y) x y
BAR(abc BC def, ghi EC jkl)

BC
#define BAZ baz
EC
BAZ