References: syscall.PR_FP_EXC

const syscall.PR_FP_EXC_UND

one use

	syscall (current package)
		zerrors_linux_amd64.go#L682: 	PR_FP_EXC_UND                    = 0x40000

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