ref: a6e8c537f7005cadda33aebfeb4ca6bd3a31b9b7
dir: /sys/src/libc/port/strcmp.c/
#include <u.h>
#include <libc.h>
int
strcmp(char *s1, char *s2)
{
	unsigned c1, c2;
	for(;;) {
		c1 = *s1++;
		c2 = *s2++;
		if(c1 != c2) {
			if(c1 > c2)
				return 1;
			return -1;
		}
		if(c1 == 0)
			return 0;
	}
}