Append files

We did not create a recipe file while creating the meta-test layer. Instead, we created an append file for the helloworld recipe, which we already have in the meta-ybdevelop layer. Append files are a mechanism used to override/enhance existing functionality in the recipe to which the append is being applied. This is the recommended way to do things. According to the guidelines, it is suggested that you use append files instead of copying the full recipe files to your layers. These files should have bbappend as an extension, and the name should be the same as the recipe to which we are applying modifications. Also, you should only be modifying the contents required by you. In this append file, we used two lines. In the first line, we extended the file lookup path to be used, as follows:

FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}-${PV}:"

In the next line, we picked the patch file to be applied to the source code file of our helloworld recipe. This is a simple patch file, which...