Instructions for creating a separate VirtualBox project and building the packages

Although it is possible to modify a project at the openSUSE Build System (OBS),
I have found it to be more convenient to use the various osc commands to create a
local copy, edit it on my own computer to fix any problems, and then push the result
to OBS.

A. Create a new sub-project:
   1. Branch the package:
	osc branch Virtualization virtualbox
   2. Checkout the package using the "osc co" command listed

B. Build the project:
   1. Use "osc build" to build. This step is rather compute intensive and
      takes about an hour on my Toshiba laptop with a dual-core Intel Core i7 CPU
      with hyper-threading, 12 GB RAM, and an SSD.
   2. The build results are stored in the /var/tmp/build-root tree. These files
      can occupy a lot of disc space, particularly when one builds several flavors.
      To keep from running out of space on the / partition, I mount /var/tmp on
      a separate partition. At present, I have used about 43 GiB in that partition.
   3. Special flavors:
      When a new kernel is released, there may be several API changes that affect
      builds of the kernel modules used by VirtualBox. In Factory, the project that
      contains the latest kernels is "Kernel-HEAD-standard". To run a test build with
      this kernel, use the command "osc build Kernel-HEAD-standard". When switching
      between kernel projects, use of the "--clean" switch is advised, otherwise
      strange "missing library" messages will result.
   4. On occasion, there may be breakage in the build when there is an update with
      python or Qt. Use the "--alternative-project=<xxx>" switch to force usage of
      the revised component.

C. Steps to take with a new release:
   1. When Orable releases a new version, you will need to download then new tarball
      from https://download.virtualbox.org/virtualbox/. While downloading the file, I
      also get the new UserManual.pdf.
   2. openSUSE makes some changes to the tarball by running the command
      bash ./virtualbox-patch-source.sh <name of tarball just downloaded>
      This command unpacks the tar file, makes some modifications to the source, and
      recreates the tar file with "patched" in its name. Any further modifications
      are made by patches that are applied during the build process. Do NOT make any
      further changes to the tar file.
   3. Edit the "Version" line near the start of virtualbox.spec to select the new version.
   4. Use "osc rm <old version>" and "osc add <new version>" to get the new file into
      osc. The local build will work without these changes, but the remote operations
      will fail.`