Re: warning: module to simplify adding compiler warnings

[Paolo Bonzini]

>>> Also, if only one argument is given, won't this do an AC_SUBST([]) ?
>> Yes.  And I thought it was a no-op (that's why I AC_SUBSTed WARN_CFLAGS
>> separately), but it gives an error.
> 
> Should AS_LITERAL_IF be taught to treat the empty argument as non-literal?

No, absolutely.  That's the purpose of things such as AS_IDENTIFIER_IF,
which is what AC_SUBST uses.

I cannot think of a use case for AS_LITERAL_IF on an empty argument, but
that's actually because I cannot think right now of a use case for
macros accepting empty arguments in general.

Paolo