static const char* Format(const va_list &vaList, const char* formatString) /*CUSTOM_PRINTF(2, 0)*/;
'''BUILD:              helperfuncs.cpp
...
/home/daniel/src/inspircd/src/helperfuncs.cpp:427:88: error: function might be possible candidate for ‘gnu_printf’ format attribute [-Werror=missing-format-attribute]'''

static const char* Format(const va_list &vaList, const char* formatString) CUSTOM_PRINTF(2, 0);
'''BUILD:              helperfuncs.cpp
BUILD:              inspircd.cpp'''