Normally variables that have a named struct as a type will get a
typedef entry as their type, sometimes however the Go linker will
decide to use the DW_TAG_structure_type entry instead.
For consistency always wrap a struct type into a typedef when we are
creating a new variables (see comment in newVariable for exceptions).
This fixes a bug where it would be impossible to call methods on a
global variable.
Implements the function call injection protocol introduced in go 1.11
by https://go-review.googlesource.com/c/go/+/109699.
This is only the basic support, see TODO comments in pkg/proc/fncall.go
for a list of missing features.
Updates #119
