move a bunch of tests from testcode/lib to test/val (and a failing one to test/todo)

test/val/strncmp-test.c

@@ -0,0 +1,24 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+static const char S1[] = {
+    'h', 'e', 'l', 'l', 'o', ' ', 'W', 'o', 'r', 'l', 'd', '\0', 'A'
+};
+
+static const char S2[] = {
+    'h', 'e', 'l', 'l', 'o', ' ', 'w', 'o', 'r', 'l', 'd', '\0', 'B'
+};
+
+
+
+
+int main (void)
+{
+    char I;
+    for (I = 0; I < 20; ++I) {
+        printf ("%02d: %d\n", I, strncmp (S1, S2, I));
+    }
+    return 0;
+}
+