On Linux this enables using named memory maps to assist profiling.

Change-Id: I96c36cf7b892237f4f7ed921d01f33454a9398f0
Reviewed-on: https://swiftshader-review.googlesource.com/20508Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>