Fix #5504: invalid warning

[thmueller64]

Fixes the invalid warning about "dummy-MIDI-client" mentioned in #5504. The implementation is similar to Mixer::tryAudioDevices, like mentioned in the issue, but prints the precise device name that failed.

[LmmsBot]

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Windows

• Windows 32-bit: lmms-1.2.1-msvc2017-win32.exe (build link)
• Windows 64-bit: lmms-1.2.1-msvc2017-win64.exe (build link)

🤖

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[Spekular]

Tested:

• ALSA Sequencer (working): Neither version prints any warnings
• ALSA Raw (failing): Both versions print three lines of warnings, but this PR is more specific on the third
  • Master: Couldn't create MIDI-client, neither with ALSA nor with OSS. Will use dummy-MIDI-client.
  • PR: Couldn't create ALSA Raw-MIDI (Advanced Linux Sound Architecture) MIDI-client. Will use dummy-MIDI-client.
• Dummy: Master prints a generic warning, this PR prints no warning

So, it makes the error message more specific, and gets rid of it when irrelevant. Seems to fix the issue from what I can tell. Code LGTM as well.

[JohannesLorenz]

Thanks for fixing and reviewing. As this is just a few printfs and some if/else, is everyone OK if we rebase this to stable-1.2?

[JohannesLorenz]

I think you force-pushed right, but we probably still need to tell github that we want to merge into stable-1.2 (by clicking the "edit" button on top right of your PR).

[JohannesLorenz]

CI was passed, see draft PR #5514 . Merging now.