By setting the RPATH to $ORIGIN, Linux executables can behave like on
Windows and search for shared libraries in the exectuables directory
before looking elsewhere. We copy SwiftShader's Vulkan library into this
directory, naming it vulkan.so.1 to match the loader name the
executables look for.

This also relies on SwiftShader exporting all Vulkan API entry functions
like the loader library does: b/148240133

Bug: b/141361933
Change-Id: I617303cc11faead7aac9e689142a4400731a58a5
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/41970Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>