_cgo_export.h   # for gcc
	_cgo_main.c     # for gcc
	_cgo_flags      # for build tool (if -gccgo)

The file x.cgo1.go is a copy of x.go with the import "C" removed and
references to C.xxx replaced with names like _Cfunc_xxx or _Ctype_xxx.
The definitions of those identifiers, written as Go functions, types,
or variables, are provided in _cgo_gotypes.go.

Here is a _cgo_gotypes.go containing definitions for needed C types:

// We have consumed the register or R prefix.
func (p *Parser) atRegisterExtension() bool {
	// ARM64 only.
	if p.arch.Family != sys.ARM64 {
		return false
	}
	// R1.xxx
	return p.peek() == '.'
}

// registerReference parses a register given either the name, R10, or a parenthesized form, SPR(10).
func (p *Parser) registerReference(name string) (int16, bool) {