[RFC PATCH 3/4] audio: Rename coreaudio extension to use Objective-C compiler

["Philippe Mathieu-Daudé via" <qemu-devel@nongnu.org>]

The coreaudio library includes Objective-C declarations (using the
caret '^' symbol to declare block references [*]). When building
with a C compiler we get:

  [175/839] Compiling C object libcommon.fa.p/audio_coreaudio.c.o
    In file included from /Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/System/Library/Frameworks/CoreAudio.framework/Headers/CoreAudio.h:18,
                     from ../../audio/coreaudio.c:26:
    /Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/System/Library/Frameworks/CoreAudio.framework/Headers/AudioHardware.h:162:2: error: expected identifier or '(' before '^' token
      162 | (^AudioObjectPropertyListenerBlock)(    UInt32                              inNumberAddresses,
          |  ^
    FAILED: libcommon.fa.p/audio_coreaudio.c.o

Rename the file to use the Objective-C default extension (.m) so
meson calls the correct compiler.

[*] https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/ProgrammingWithObjectiveC/WorkingwithBlocks/WorkingwithBlocks.html

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 audio/{coreaudio.c => coreaudio.m} | 0
 audio/meson.build                  | 2 +-
 2 files changed, 1 insertion(+), 1 deletion(-)
 rename audio/{coreaudio.c => coreaudio.m} (100%)

diff --git a/audio/coreaudio.c b/audio/coreaudio.m
similarity index 100%
rename from audio/coreaudio.c
rename to audio/coreaudio.m
diff --git a/audio/meson.build b/audio/meson.build
index d9b295514f..94dab16891 100644
--- a/audio/meson.build
+++ b/audio/meson.build
@@ -7,7 +7,7 @@ softmmu_ss.add(files(
   'wavcapture.c',
 ))
 
-softmmu_ss.add(when: coreaudio, if_true: files('coreaudio.c'))
+softmmu_ss.add(when: coreaudio, if_true: files('coreaudio.m'))
 softmmu_ss.add(when: dsound, if_true: files('dsoundaudio.c', 'audio_win_int.c'))
 
 audio_modules = {}
-- 
2.34.1