Both windows and linux do this already using .def files and linker scripts, respectfully.
Mac's linker has the exported_symbols_list flag that acts similarly.

This is required as the SPIRV-Tools in dEQP now collides with the version in SwiftShader, leading to horribly cryptic crashes deep in SPIRV structures.

Change-Id: I3641744ae2439bf05468b6f10cf3da0307614534
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/32568
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Tested-by: Ben Clayton <bclayton@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Chris Forbes <chrisforbes@google.com>