Adds support for building Snap on Windows and FreeBSD

[jcooklin]

Fixes: #1527
Related: #1506 #671

Summary of changes:

• Adds portability of build scripts so building works on
  • FreeBSD
  • Windows

Testing done:

• Built snap on
  • FreeBSD
  • Windows
    • caveats
      • required: MinGW
      • Makefile is not supported (use scripts directly)
        • scripts/deps.sh
        • scripts/build_all.sh
        • ....
  • Darwin
  • Linux

Windows:

FreeBSD:

cc: @brd @swills @stdale @jessemillar

This PR incorporates work done by @brd @stdale @IRCody for making snap build on FreeBSD and @jessemillar for Windows. Thanks for your contributions.

@intelsdi-x/snap-maintainers

[kjlyon]

👍

[brd]

Nice! Thanks for helping get this support in.

I don't suppose you guys have contacts at Travis-CI? It would be nice to have you guys lean on them to provide FreeBSD Builders. I know a bunch of people have asked, but they are dragging their feet.

[swills]

I've setup a Jenkins build job for this, you can view it here:

https://jenkins.mouf.net/job/intelsdi-x-snap/

For now it's pointing at jcooklin's fb/portable-build branch. I can update it when this is merged.

[nanliu]

@swills, nice! We can duplicate the job in https://ci.snap-telemetry.io/ and add the webhooks in github so you don't have to host it.

@brd, we have support with travis, but not sure that will move the needle. I can send them an email and see where that takes us.

[swills]

@nanliu Cool. You'll have to setup a FreeBSD based build slave for Jenkins.

[jessemillar]

👍

[brd]

@nanliu Thanks for helping all the same :)