[9fans] ape strtod crash

[roger peppe]

this ape program gives a floating point exception error:

#include <stdlib.h>
void
main(){
        strtod("421567849e316", 0);
}

this made awk crash when i was running dumpvacroots.
it dies at /sys/src/ape/lib/ap/stdio/strtod.c:473
but it looks a bit involved for me to dive into right now,
i'm afraid.