ENH: Add extra test files

Tests/SubDir/AnotherSubdir/secondone.c

@@ -0,0 +1,4 @@
+const char* secondone()
+{
+  return "Hello again";
+}

Tests/SubDir/AnotherSubdir/testfromsubdir.c

@@ -0,0 +1,10 @@
+#include <stdio.h>
+
+const char* secondone();
+
+int main()
+{
+  printf("Hello from subdirectory\n");
+  printf("SO: %s\n", secondone());
+  return 0;
+}