add: strncmp

src/string/strncmp.c

@@ -0,0 +1,12 @@
+#include <stddef.h>
+
+int strncmp(const char *s1, const char *s2, size_t n)
+{
+	size_t i = 0;
+
+	if (n == 0)
+		return 0;
+	while (s1[i] == s2[i] && i < (n - 1))
+		i++;
+	return s1[i] - s2[i];
+}