ref: 72f9c4e49acb9d8d7397b6ea7de53ec9899a054c
dir: /sys/src/libc/port/runestrchr.c/
#include <u.h>
#include <libc.h>
Rune*
runestrchr(Rune *s, Rune c)
{
	Rune c0 = c;
	Rune c1;
	if(c == 0) {
		while(*s++)
			;
		return s-1;
	}
	while(c1 = *s++)
		if(c1 == c0)
			return s-1;
	return 0;
}