Allow Empty Format Strings in Error Macro Invocations

Allow Empty Format Strings in Error Macro Invocations

`-Wall` implies `-Wformat-zero-length`, which will cause compilation to fail
under `-Werror` when an empty string is passed as the format string to a
`printf`-family function. This commit moves us back to prefixing the provided
format string, which successfully avoids that warning.

However, this removes the failure mode where that `RAWLOG` invocation would
fail to compile when no format string was provided at all (which was desirable
to avoid having code that would successfully compile normally but fail under
`-pedantic`, which *does* require that a non-zero number of args are provided).

So this commit also introduces a function which does nothing at all, but will
fail to compile if not provided with at least one argument, which is a string.
This successfully links the compilability of pedantic and non-pedantic builds.