apps: qcam: Disable -Wextra-semi

The Qt 6 qkeysequence.h header has an extra semicolon. This causes a
build failure with clang:

/usr/include/qt6/QtGui/qkeysequence.h:139:26: error: extra ';' after member function definition [-Werror,-Wextra-semi]
  139 |     Q_ENUM(SequenceMatch);
      |                          ^

We can't fix the issue, so ignore the warning in qcam.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Milan Zamazal <mzamazal@redhat.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>

src/apps/qcam/meson.build

@@ -36,7 +36,11 @@ qcam_resources = files([
     'assets/shader/shaders.qrc',
 ])
 
-qt6_cpp_args = [apps_cpp_args, '-DQT_NO_KEYWORDS']
+qt6_cpp_args = [
+    apps_cpp_args,
+    '-DQT_NO_KEYWORDS',
+    '-Wno-extra-semi',
+]
 
 resources = qt6.preprocess(moc_headers : qcam_moc_headers,
                            qresources : qcam_resources,