Various additions and fixes.

src/lib9/cistrncmp.c

@@ -0,0 +1,28 @@
+#include <u.h>
+#include <libc.h>
+
+int
+cistrncmp(char *s1, char *s2, int n)
+{
+	int c1, c2;
+
+	while(*s1 && n-- > 0){
+		c1 = *(uchar*)s1++;
+		c2 = *(uchar*)s2++;
+
+		if(c1 == c2)
+			continue;
+
+		if(c1 >= 'A' && c1 <= 'Z')
+			c1 -= 'A' - 'a';
+
+		if(c2 >= 'A' && c2 <= 'Z')
+			c2 -= 'A' - 'a';
+
+		if(c1 != c2)
+			return c1 - c2;
+	}
+	if(n <= 0)
+		return 0;
+	return -*s2;
+}