Make UserlandFS an actual HPKG via build system

[mmadia]

By making UserlandFS an actual HPKG, it could be included in the default image as a non-activated package. This would make testing easier for end users.

​build/jam/OptionalPackages contains the pre-package management code. ​build/jam/packages contains several working examples.

[jalopeura]

Notes:

• Two hpkg files are generated: userlandfs.hpkg and userlandfs_devel.hpkg.

• If you also have the Development package in your build, it will automatically create the second hpkg file; otherwise you only get the main file.

• I don't know how to add a non-activated package, so it just follows the old method: you need to add UserlandFS as an optional package in your UserBuildConfig.

• I did not verify that the files in the package work; I merely verfied that the packages were created and that when I moved them into system/packages, the files showed up in the right places.

[waddlesplash]

Please correct the following:

• Copyright should say 2014 not 2013
• Patch should be in Git AM format (can be obtained by committing and then running git format-patch -1)

Otherwise looks OK to me, but I'm no Jam wizard.

[jalopeura]

Corrections made.

I'm not a jam expert either. I just copied and modified existing files. All I care about is that the patch is generated and recognized by packagefs.

[bonefish]

I haven't looked too closely at the package definition, but basically the patch looks good. However the part in build/jam/OptionalPackages should be removed completely. It is superfluous, since one can just as well add the AddPackageFilesToHaikuImage invocation to UserBuildConfig instead of AddOptionalHaikuImagePackages.

The packages should be added to build/jam/repositories/Haiku, though. This will add them to the package repository.

[jalopeura]

If I put them in build/jam/repositories/Haiku, will they automatically be added to the repository, or do I still need to add something in UserBuild Config?

[bonefish]

build/jam/repositories/Haiku defines what end up in the package repository. Once such a change has been pushed to the central repository, the next BuildBot run will automatically create and publish a package repository with the new package included.

[pulkomandy]

Done in hrev48317.