}
	return args[:len(args):len(args)], nil
}

// gccMachine returns the gcc -m flag to use, either "-m32", "-m64" or "-marm".
func (p *Package) gccMachine() []string {
	switch goarch {
	case "amd64":
		if goos == "darwin" {
			return []string{"-arch", "x86_64", "-m64"}
		}
		return []string{"-m64"}
	case "arm64":
		if goos == "darwin" {
			return []string{"-arch", "arm64"}
		}

effect to systems satisfying one of the constraints
(see https://golang.org/pkg/go/build/#hdr-Build_Constraints for details about the constraint syntax).
For example:

	// #cgo CFLAGS: -DPNG_DEBUG=1
	// #cgo amd64 386 CFLAGS: -DX86=1
	// #cgo LDFLAGS: -lpng
	// #include <png.h>
	import "C"

Alternatively, CPPFLAGS and LDFLAGS may be obtained via the pkg-config tool
using a '#cgo pkg-config:' directive followed by the package names.