Xattrs map[string]string

	// PAXRecords is a map of PAX extended header records.
	//
	// User-defined records should have keys of the following form:
	//	VENDOR.keyword
	// Where VENDOR is some namespace in all uppercase, and keyword may
	// not contain the '=' character (e.g., "GOLANG.pkg.version").
	// The key and value should be non-empty UTF-8 strings.
	//

The CXX_FOR_TARGET, CXX_FOR_${GOOS}_${GOARCH}, and CXX
environment variables work in a similar way for C++ code.

# Go references to C

Within the Go file, C's struct field names that are keywords in Go
can be accessed by prefixing them with an underscore: if x points at a C
struct with a field named "type", x._type accesses the field.
C struct fields that cannot be expressed in Go, such as bit fields

	fld := make([]*ast.Field, 0, 2*len(dt.Field)+1) // enough for padding around every field
	sizes := make([]int64, 0, 2*len(dt.Field)+1)
	off := int64(0)

	// Rename struct fields that happen to be named Go keywords into
	// _{keyword}.  Create a map from C ident -> Go ident. The Go ident will
	// be mangled. Any existing identifier that already has the same name on
	// the C-side will cause the Go-mangled version to be prefixed with _.