configure: Define OS_OBJECT_USE_OBJC=0 for MacOSX builds

MacOSX 10.8 ("Mountain Lion") defaults to trying to use automated
reference counting on certain objects.  This means that the system
header files will use some Objective C syntax constructs even when
compiling pure C, which confuses mainline gcc. Suppress this by
setting OS_OBJECT_USE_OBJC=0. This avoids a compile error like this:

In file included from
/System/Library/Frameworks/Foundation.framework/Headers/NSObject.h:5:0,
                 from /usr/include/os/object.h:74,
                 from /usr/include/dispatch/dispatch.h:48,
                 from /System/Library/Frameworks/IOKit.framework/Headers/IOKitLib.h:56,
                 from block/raw-posix.c:35:
/System/Library/Frameworks/Foundation.framework/Headers/NSObjCRuntime.h:409:1: error: stray ‘@’ in program
[with a large number of further run-on errors]

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/configure b/configure
index d08c0ce028..6f6f8e03f0 100755
--- a/configure
+++ b/configure
@@ -467,6 +467,9 @@ Darwin)
   audio_possible_drivers="coreaudio sdl fmod"
   LDFLAGS="-framework CoreFoundation -framework IOKit $LDFLAGS"
   libs_softmmu="-F/System/Library/Frameworks -framework Cocoa -framework IOKit $libs_softmmu"
+  # 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.
+  QEMU_CFLAGS="-DOS_OBJECT_USE_OBJC=0 $QEMU_CFLAGS"
 ;;
 SunOS)
   solaris="yes"