Move C files to be included by go mod

[afontaine]

Fixes #832 by moving the C files into a go module directory, which means they should be included by go mod vendor.

Not sure how I should name them, let me know if you want it changed.

[afontaine]

well, so much for this being easy 😞

I don't really understand the error here either, do you have any insight @shirou?

[afontaine]

oh hey that did the trick. I am a touch concerned that this would somehow still not work though 🤔 but my C seems to think that this should work

[shoenig]

I believe this breaks compatibility with non-darwin targets

$ uname -a
Linux nzxt 5.4.0-33-generic #37-Ubuntu SMP Thu May 21 12:53:59 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

$ cat go.mod
module foo

go 1.14

replace github.com/shirou/gopsutil => github.com/afontaine/gopsutil v2.20.5-0.20200528220053-51e143da77b3+incompatible

require (
	github.com/shirou/gopsutil v0.0.0-00010101000000-000000000000
	golang.org/x/sys v0.0.0-20200523222454-059865788121 // indirect
)

$ cat foo.go
package main

import _ "github.com/shirou/gopsutil/host"

$ go build
foo.go:3:8: C source files not allowed when not using cgo or SWIG: smc.c

$ CGO_ENABLED=1 go build
foo.go:3:8: C source files not allowed when not using cgo or SWIG: smc.c

[afontaine]

Ah... yes, of course it's not that simple 🤔

[Lomanic]

You have to rename smc.c to smc_darwin.c and smc.h to smc_darwin.h and change the references in the source and it's then possible to go build github.com/shirou/gopsutil/hoston Linux successfully. This is what I've done in #832 (comment). Though I prefer your names (smc_darwin.{c,h} compared to my less descriptive host_darwin.{c,h}).

Though there were the same compilation warnings with these changes, I fixed them in my own branch (I'm quite sure I wouldn't be able to push to your branch) and took the occasion to rename darwin c files in the disk package.

As you spent some time on it and want some attribution maybe, I can let you fix that in your branch and merge this PR afterwards, I will rebase my PR after merging yours if you do so.

[afontaine]

Ah the magic of go! Thanks @Lomanic

I'm not super concerned about the attribution, more about the fix 😁 I updated the file names, and I don't really know what I'm doing with go 😅

[afontaine]

@Lomanic by all means please merge #889 instead of this, as it looks like you've captured more files that need to be moved/renamed 👍

[Lomanic]

OK, no problem.