The C variadic spellings ("..." and the GNU "name..."), an empty or
trailing parameter, a missing comma, a stray token and an unterminated
list all parsed silently before: non-identifier tokens were skipped, so
"#define M(...)" defined a zero-parameter macro and invocations were
diagnosed only by argument count, if at all. The toolchain rejects the
definition itself ("bad definition for macro"), and so does the
preprocessor now: the parameter list must be identifiers separated by
single commas and closed by the parenthesis, and a rejected definition
leaves the name unbound. The spellings join the fuzz corpus.
Assisted-by: GLM 5.3
petrbalvin
63ed141522