Errors from :GoBuild and similar commands don't look very good

[arp242]

Running :GoBuild -tags=foo is an error; this shows as:

Which is not great; I need to type :messages to get the full error:

which is formatted pretty badly. Newlines are lost, and tabs are represented as <09>.

This is not a problem with just this command; I've seen it in many commands. In fact, it's the prime reason I typically use :!go ... instead of :Go.

Investigate if this can be improved.

[arp242]

Also noticed Neovim does't display errors beyond the first few characters; e.g.:

vim-go: building dispatched ...
vim-go: [build] FAILED
vim-go: # a

Regular Vim:

vim-go: building dispatched ...
vim-go: FAILED
vim-go: # a runtime.main_main·f: relocation target main.main not defined runtime.main_main·f: undefined: "main.main
"
vim-go: /home/martin/go/src/a

[arp242]

And for Vim 7.4 there is basically no error output at all? I can't find anything in the quickfix list, location list, or :messages.