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

one use

	golang.org/x/sys/unix (current package)
		zsysnum_linux_amd64.go#L121: 	SYS_GETPGRP                 = 111

The pages are generated with Golds v0.4.9. (GOOS=linux GOARCH=amd64)