When set to false, the -dolinkobj flag instructs the compiler
not to generate or emit linker information.
This is handy when you need the compiler's export data,
e.g. for use with go/importer,
but you want to avoid the cost of full compilation.
This must be used with care, since the resulting
files are unusable for linking.
This CL interacts with #18369,
where adding gcflags and ldflags to buildid has been mooted.
On the one hand, adding gcflags would make safe use of this
flag easier, since if the full object files were needed,
a simple 'go install' would fix it.
On the other hand, this would mean that
'go install -gcflags=-dolinkobj=false' would rebuild the object files,
although any existing object files would probably suffice.