_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: