ref: 415045a10f1152b4daa9ba1d271b3b5a86d93fe7
dir: /sys/src/libString/s_putc.c/
#include <u.h>
#include <libc.h>
#include "String.h"
void
s_putc(String *s, int c)
{
	if(s->ref > 1)
		sysfatal("can't s_putc a shared string");
	if (s->ptr >= s->end)
		s_grow(s, 2);
	*(s->ptr)++ = c;
}