const golang.org/x/sys/unix.PerfBitExcludeCallchainKernel

one use

	golang.org/x/sys/unix (current package)
		ztypes_linux.go#L1125: 	PerfBitExcludeCallchainKernel        = CBitFieldMaskBit21

The pages are generated with Golds v0.7.6. (GOOS=linux GOARCH=amd64)