https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71855
--- Comment #2 from Ben Woodard <woodard at redhat dot com> --- This is about as simple of a reproducer as I have been able to come up with: #define _GNU_SOURCE #include <stdarg.h> #include <stdlib.h> #include <stdio.h> void m4_error (int status, int errnum, const char *format, ...) { va_list args; char *result; va_start (args, format); vasprintf (&result, format, args); va_end (args); }