Fix Makefile compatiblity with Make 3.81

[danmichaelo]

Turned out to be easy to fix #251 , it's just newline handling that has changed. It now works both with make 3.81 and 4.3:

$ rm ~/gocode/bin/golangci-lint
$ make lint
golangci/golangci-lint info checking GitHub for tag 'v1.43.0'
golangci/golangci-lint info found version: 1.43.0 for v1.43.0/darwin/amd64
golangci/golangci-lint info installed ~/gocode/bin/golangci-lint
golangci-lint run ./...

$ rm ~/gocode/bin/golangci-lint
$ gmake lint
golangci/golangci-lint info checking GitHub for tag 'v1.43.0'
golangci/golangci-lint info found version: 1.43.0 for v1.43.0/darwin/amd64
golangci/golangci-lint info installed ~/gocode/bin/golangci-lint

[realtime-neil]

@danmichaelo with this change, you could probably also lose the GNUism .ONESHELL at the top.

[danmichaelo]

@danmichaelo with this change, you could probably also lose the GNUism .ONESHELL at the top.

Interesting, that could very well be, but I'm not at all familiar with that option or why it's there, so I don't feel confident suggesting to remove it.

[ankitpokhrel]

@danmichaelo @realtime-neil .ONESHELL is only supported from 3.82. Mac is shipped with 3.81 and since we are not extensively relying on .ONESHELL, I am good with removing it for improved support.