uc_onstack  int32
	uc_sigmask  uint32
	uc_stack    stackt
	uc_link     *ucontext
	uc_mcsize   uint64
	uc_mcontext *mcontext64
}

type keventt struct {
	ident  uint64
	filter int16
	flags  uint16
	fflags uint32
	data   int64
	udata  *byte
}

type pthread uintptr
type pthreadattr struct {
	X__sig    int64
	X__opaque [56]int8
}
type pthreadmutex struct {
	X__sig    int64

    return all_files

# Collects all the flags used in golang files and verifies the flags do
# not contain underscore. If any flag needs to be excluded from this check,
# need to add that flag in hack/verify-flags/excluded-flags.txt.
def check_underscore_in_flags(rootdir, files):
    # preload the 'known' flags which don't follow the - standard
    pathname = os.path.join(rootdir, "hack/verify-flags/excluded-flags.txt")
    f = open(pathname, 'r')

}

type itimerval struct {
	it_interval timeval
	it_value    timeval
}

type umtx_time struct {
	_timeout timespec
	_flags   uint32
	_clockid uint32
}

type keventt struct {
	ident  uint32
	filter int16
	flags  uint16
	fflags uint32
	data   int64
	udata  *byte
	ext    [4]uint64
}

type bintime struct {
	sec  int32
	frac uint64
}

}

type itimerval struct {
	it_interval timeval
	it_value    timeval
}

type umtx_time struct {
	_timeout timespec
	_flags   uint32
	_clockid uint32
}

type keventt struct {
	ident  uint64
	filter int16
	flags  uint16
	fflags uint32
	data   int64
	udata  *byte
	ext    [4]uint64
}

type bintime struct {
	sec  int64
	frac uint64
}

}

type itimerval struct {
	it_interval timeval
	it_value    timeval
}

type umtx_time struct {
	_timeout timespec
	_flags   uint32
	_clockid uint32
}

type keventt struct {
	ident     uint32
	filter    int16
	flags     uint16
	fflags    uint32
	pad_cgo_0 [4]byte
	data      int64
	udata     *byte
	pad_cgo_1 [4]byte
	ext       [4]uint64
}

type bintime struct {

}

type itimerval struct {
	it_interval timeval
	it_value    timeval
}

type umtx_time struct {
	_timeout timespec
	_flags   uint32
	_clockid uint32
}

type keventt struct {
	ident  uint64
	filter int16
	flags  uint16
	fflags uint32
	data   int64
	udata  *byte
	ext    [4]uint64
}

type bintime struct {
	sec  int64
	frac uint64
}

// and "go version <binary>" if it differs from the default experiments.
//
// For the set of experiments supported by the current toolchain, see
// "go doc goexperiment.Flags".
//
// Note that this package defines the set of experiments (in Flags)
// and records the experiments that were enabled when the package
// was compiled (as boolean and integer constants).
//
// Note especially that this package does not itself change behavior

}

type itimerval struct {
	it_interval timeval
	it_value    timeval
}

type umtx_time struct {
	_timeout timespec
	_flags   uint32
	_clockid uint32
}

type keventt struct {
	ident  uint64
	filter int16
	flags  uint16
	fflags uint32
	data   int64
	udata  *byte
	ext    [4]uint64
}

type bintime struct {
	sec  int64
	frac uint64
}

		extraLDFlags := ""
		if strings.Contains(testenv.Builder(), "clang") {
			extraLDFlags += " -fuse-ld=lld"
		}
		const cflags = "-flto -Wno-lto-type-mismatch -Wno-unknown-warning-option"
		cmd.Env = append(cmd.Environ(),
			"CGO_CFLAGS="+cflags,
			"CGO_CXXFLAGS="+cflags,
			"CGO_LDFLAGS="+cflags+extraLDFlags)
	}
	out, err := cmd.CombinedOutput()
	if string(out) != "OK\n" {
		t.Errorf("%s", string(out))
	}

[!GOOS:darwin] skip
[!cgo] skip

! go build
stderr 'invalid flag in #cgo LDFLAGS: -lto_library'

-- go.mod --
module ldflag

-- main.go --
package main

// #cgo CFLAGS: -flto
// #cgo LDFLAGS: -lto_library bad.dylib
import "C"