for __cgo__N to learn the type of each identifier. (The types also
distinguish functions from global variables.) Cgo reads the constant
values from the __cgodebug_* from the object file's data segment.

At this point cgo knows the meaning of each C.xxx well enough to start
the translation process.

Translating Go

Given the input Go files x.go and y.go, cgo generates these source
files: