Fix linking errors with LIBSCSYNTH=ON

[mossheim]

Purpose and Motivation

This fixes #5013, as well as another linking error with LIBSCSYNTH

On linux, building with LIBSCSYNTH=ON and SYSTEM_BOOST=OFF fails with linking errors because
a static library is being linked into a shared library. solved by compiling the offending library with -fPIC.

On macOS, building with LIBSCSYNTH=ON fails with linking errors because SC_EventLoop.hpp functions used in
scsynth's main() are hidden, similar to what we encountered in #4992. This PR solves the issue the same way as
#5012, by including the file in scsynth rather than libscsynth (and doing the equivalent change for supernova).
This required separating out the event loop-specific functions into a new header and implementation file since
disableAppNap is not used in quite the same way.

Types of changes

• Bug fix

To-do list

• Code is tested - i've cherry picked these tentatively into add CI jobs to implement platform support RFC #4906, where you can see that both LIBSCSYNTH builds
  succeed
• All tests are passing
• Updated documentation
• This PR is ready for review

[sonoro1234]

@brianlheim Sorry, I cant review this PR because my macos knowledge is really bad, I dont even have one.

[mossheim]

@sonoro1234 -- ok, no worries. @Spacechild1 or @joshpar , perhaps you could give this a quick look?

[Spacechild1]

Who is Seth Nickell? ;-)

[mossheim]

not sure! this was in the file before, and you kept it when you added your functions. do you want the copyright assignment then?

[Spacechild1]

ah, I see! well, I would be flattered :-)

[Spacechild1]

see above

[Spacechild1]

Apart from that it looks fine! The event loops certainly belongs to the scsynth/supernova apps.

Note that people can still use the event loop with libscsynth, they just have to include common/SC_AppleEventLoop.cpp in their project and start the event loop manually (once).

[joshpar]

I’m guessing event loop code came from another source. I’m ok adding attribution, but I prefer not to remove any previous ones. /* Josh Parmenter www.realizedsound.net/josh */

…

On Jun 14, 2020, at 09:24, Brian Heim ***@***.***> wrote:  @brianlheim commented on this pull request. In common/SC_AppleEventLoop.hpp: > @@ -0,0 +1,34 @@ +/************************************************************************ + * + * Copyright 2013 Seth Nickell ***@***.***> not sure! this was in the file before, and you kept it when you added your functions. do you want the copyright assignment then? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub, or unsubscribe.

[mossheim]

I’m guessing event loop code came from another source.

@Spacechild1 is the one who added the event loop code, that's why i asked if they wanted attribution. :) removing Seth Nickell's name here would not be removing attribution, because they did not contribute any of that code.

[joshpar]

I’m wondering if that is the author of some code (or even sample code) that was used for this bit of code that @Spacechild1 was including as reference. If not, I’m totally fine removing it as well.

…

On Jun 14, 2020, at 09:56, Brian Heim ***@***.***> wrote:  I’m guessing event loop code came from another source. @Spacechild1 is the one who added the event loop code, that's why i asked if they wanted attribution. :) removing Seth Nickell's name here would not be removing attribution, because they did not contribute any of that code. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub, or unsubscribe.

[Spacechild1]

I’m wondering if that is the author of some code (or even sample code) that was used for this bit of code

Seth Nickell was not involved in the event loop code. He probably wrote the void disableAppNap(); which was the only function in the SC_Apple.hpp before I added the event loop. The sample code I've referenced is by another author.

[mossheim]

@joshpar @Spacechild1 updated!

[bagong]

Seth Nickell was not involved in the event loop code. He probably wrote the void disableAppNap(); which was the only function in the SC_Apple.hpp before I added the event loop. The sample code I've referenced is by another author.

Yes, that's true, I remember Seth turning up out of nowhere when AppNap was giving people a little scare ;-)