darwin: detect CoreAudio for build

On iOS there is no CoreAudio, so we should not assume Darwin always
has it.

Signed-off-by: Joelle van Dyne <j@getutm.app>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20210126012457.39046-11-j@getutm.app
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

configure

@@ -319,6 +319,7 @@ fdt="auto"
 netmap="no"
 sdl="auto"
 sdl_image="auto"
+coreaudio="auto"
 virtiofsd="auto"
 virtfs="auto"
 libudev="auto"
@@ -778,7 +779,7 @@ Darwin)
     QEMU_CFLAGS="-arch x86_64 $QEMU_CFLAGS"
     QEMU_LDFLAGS="-arch x86_64 $QEMU_LDFLAGS"
   fi
-  audio_drv_list="coreaudio try-sdl"
+  audio_drv_list="try-coreaudio try-sdl"
   audio_possible_drivers="coreaudio sdl"
   # Disable attempts to use ObjectiveC features in os/object.h since they
   # won't work when we're compiling with gcc as a C compiler.
@@ -3146,6 +3147,24 @@ EOF
   fi
 fi
 
+##########################################
+# detect CoreAudio
+if test "$coreaudio" != "no" ; then
+  coreaudio_libs="-framework CoreAudio"
+  cat > $TMPC << EOF
+#include <CoreAudio/CoreAudio.h>
+int main(void)
+{
+  return (int)AudioGetCurrentHostTime();
+}
+EOF
+  if compile_prog "" "$coreaudio_libs" ; then
+    coreaudio=yes
+  else
+    coreaudio=no
+  fi
+fi
+
 ##########################################
 # Sound support libraries probe
 
@@ -3202,8 +3221,20 @@ for drv in $audio_drv_list; do
     fi
     ;;
 
-    coreaudio)
+    coreaudio | try-coreaudio)
+    if test "$coreaudio" = "no"; then
+      if test "$drv" = "try-coreaudio"; then
+        audio_drv_list=$(echo "$audio_drv_list" | sed -e 's/try-coreaudio//')
+      else
+        error_exit "$drv check failed" \
+                "Make sure to have the $drv is available."
+      fi
+    else
       coreaudio_libs="-framework CoreAudio"
+      if test "$drv" = "try-coreaudio"; then
+        audio_drv_list=$(echo "$audio_drv_list" | sed -e 's/try-coreaudio/coreaudio/')
+      fi
+    fi
     ;;
 
     dsound)