Add more tests from stringlib

tests/string_memcpy.c

@@ -0,0 +1,16 @@
+#include "string.h"
+
+int main(void)
+{
+  char testblock[8] = {1, 2, 3, 4, 5, 6, 7, 8};
+  char testblock2[6] = {50, 60, 70, 80, 90, 100};
+  int i = 0;
+
+  memcpy((void *)&testblock, (void *)&testblock2, (sizeof(char)*6));
+  for ( i = 0; i < 6; i++) {
+    if ( testblock[i] != testblock2[i] ) return (i + 1);
+  }
+  if ( testblock[6] != 7 ) return 7;
+  if ( testblock[7] != 8 ) return 8;
+  return 0;
+}