Variadic arguments weren't using the ## prefix, and causing build failures on certain compilers.

Also always `printf()` the "Waiting for debugger connection..." message. If we're debugging, then writing to `stdout` isn't an offence.

Bug: b/145351270
Change-Id: I2f86b118043ef2b2b6d291834c9f134a4db5c18d
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/40091Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Ben Clayton <bclayton@google.com>