Fix PRINTF_ARG define for gcc
Fix PRINTF_ARG define for gcc

Argument position was shifted with commit:
Remove unused argument of send_http_error

GerHobbelt/civet-webserver,GerHobbelt/civet-webserver,GerHobbelt/civet-webserver,GerHobbelt/civet-webserver,GerHobbelt/civet-webserver,GerHobbelt/civet-webserver