used.

In internal mode, cmd/link itself processes all the host object files, in
particular foo.cgo2.o. To do so, it uses the cgo_import_dynamic and
cgo_dynamic_linker directives to learn that the otherwise undefined
reference to sin in foo.cgo2.o should be rewritten to refer to the
symbol sin with version GLIBC_2.2.5 from the dynamic library