libgl-gdi: support building without softpipe
While we do need some fallback-driver, there's no good reason to always require that to be Softpipe. LLVMpipe for instance does the job just fine.
This makes the minimal build a bit smaller on Windows.
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While we do need some fallback-driver, there's no good reason to always require that to be Softpipe. LLVMpipe for instance does the job just fine.
This makes the minimal build a bit smaller on Windows.