Single spot where an existing hint ptr was overwritten. Removed gwbuf_add_hint()
because it was adding hints at the opposite end compared to functions in hint.h.
Added hint_splice() to replace.
- All now include maxscale/cdefs.h as the very first file.
- MXS_[BEGIN|END]_DECLS added to all C-headers.
Strictly speaking not necessary for private headers, but
does not hurt either.
- Include guards moved to the very top of the file.
- #pragma once added.
- Headers now to be included as <maxscale/xyz.h>
- First step, no cleanup of headers has been made. Only moving
from one place to another + necessary modifications.