cmd/link, cmd/internal/obj: use aux symbol for global variable DWARF info
Currently, for a global variable, its debug info symbol is a named
symbol with the variable's name with a special prefix. And the
linker looks it up by name. This CL makes the debug info symbol an
aux symbol of the variable symbol.
Change-Id: I55614d0ef2af9c53eb40144ad80e09339bf3cbee
Reviewed-on: https://go-review.googlesource.com/c/go/+/490816
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Than McIntosh <thanm@google.com>