Add Cgo support for NetBSD

[TotallyGamerJet]

What issue is this addressing?

Updates #249

What type of issue is this addressing?

feature

What this PR does | solves

Allows compiling with purego on NetBSD when there is a C compiler

[hajimehoshi]

Just out of curiosity, can't we use -fPIC for other platforms than FreeBSD and NetBSD?

[hajimehoshi]

Let's add to build tests for NetBSD in other platforms (e.g. Can we build a NetBSD binary in FreeBSD?)

            # Check cross-compiling NetBSD binaries.
            env GOOS=netbsd GOARCH=amd64 go build -v ./...
            env GOOS=netbsd GOARCH=arm64 go build -v ./...

[TotallyGamerJet]

I'm not sure if it's possible. We'd need to explicitly enable cgo since it's a cross compile. I'll try once the build in NetBSD is working

[TotallyGamerJet]

@0-wiz-0 I'm trying to finish up this PR so it can be merged but I can't figure out how to install go in the NetBSD environment. Could you look at the test.yml file?

[0-wiz-0]

Thank you for working on this, @TotallyGamerJet !
I looked at test.yml. You are using the upstream go binaries. They are distributed in a standard tarball, not as a pkgsrc package, so just unpack the tarball and use it - do not use pkg_add.
A prepare step like this should probably work:

          prepare: |
            ftp https://go.dev/dl/go${{matrix.go}}.netbsd-amd64.tar.gz
            rm -fr /usr/local/go && tar -C /usr/local -xf go${{matrix.go}}.netbsd-amd64.tar.gz
            ln -s /usr/local/go/bin/go /usr/local/bin

(Btw, cross-compilation to NetBSD should also work as usual in go.)

[TotallyGamerJet]

Thanks for the help. I'm getting some weird error when opening the archive. Thoughts?

(Btw, cross-compilation to NetBSD should also work as usual in go.)

This PR currently only supports Cgo. Once I get it in a usable state I can work on getting the entirely go version working which would enable cross compiling

[0-wiz-0]

I see:

 ln -s /usr/local/go/bin/go /usr/local/bin
  /usr/bin/bash /home/runner/work/_actions/vmactions/netbsd-vm/v1/run.sh execSSHSH
  Config file: netbsd-10.0.conf
  FFFFFFFFFFFFFFFF:error:0A000126:SSL routines:ssl3_read_n:unexpected eof while reading:/usr/src/crypto/external/bsd/openssl/dist/ssl/record/rec_layer_s3.c:303:

you can ignore this, it's a bogus warning that will be fixed in 10.1.

  tar: could not chdir to '/usr/local'
  
  ln: /usr/local/bin: No such file or directory

Seems we need to add

mkdir /usr/local

before the tar command.
I didn't know that the target directory needed to exist first, sorry.

[0-wiz-0]

I just saw the CI run failure - some part of the process tries running /usr/bin/bash but that is not a default shell on NetBSD.
NetBSD provides /bin/sh, /bin/csh, and /bin/ksh, any of which is probably enough for doing CI stuff.
(Bash is installable as a package, if it's really needed.)

[TotallyGamerJet]

Not sure what exactly I did to fix it but it's workin now! :D