Not only does every va_start() need a corresponding va_end(), this is
also true for va_end(). Thus, buffer_addvf() needs to call va_end().
Found by Codacy.
Signed-off-by: Uli Schlachter <psychon@znc.in>
Every .c file has to include the corresponding .h file first to make sure the
headers are self-contained. Additionally, this moves some unneeded includes
around.
Signed-off-by: Uli Schlachter <psychon@znc.in>
