meson: add -Wno-unused also to C++ args when gst debug system is disabled

And check if argument is supported instead of just passing it blindly,
and make meson code slightly cleaner, centralising the argument setting
in one place.

diff --git a/meson.build b/meson.build
index a112083..8653c8f 100644 (file)
--- a/meson.build
+++ b/meson.build
@@ -334,28 +334,25 @@ else
   cdata.set('DISABLE_ORC', 1)
 endif
 
+# Disable compiler warnings for unused variables and args if gst debug system is disabled
 if gst_dep.type_name() == 'internal'
-    gst_proj = subproject('gstreamer')
-
-    if not gst_proj.get_variable('gst_debug')
-        message('GStreamer debug system is disabled')
-        add_project_arguments('-Wno-unused', language: 'c')
-    else
-        message('GStreamer debug system is enabled')
-    endif
+  gst_debug_disabled = not subproject('gstreamer').get_variable('gst_debug')
 else
-    # We can't check that in the case of subprojects as we won't
-    # be able to build against an internal dependency (which is not built yet)
-    if not cc.compiles('''
-#include <gst/gstconfig.h>
-#ifdef GST_DISABLE_GST_DEBUG
-#error "debugging disabled, make compiler fail"
-#endif''' , dependencies: gst_dep)
-        message('GStreamer debug system is disabled')
-        add_project_arguments('-Wno-unused', language: 'c')
-    else
-        message('GStreamer debug system is enabled')
-    endif
+  # We can't check that in the case of subprojects as we won't
+  # be able to build against an internal dependency (which is not built yet)
+  gst_debug_disabled = cc.has_header_symbol('gst/gstconfig.h', 'GST_DISABLE_GST_DEBUG', dependencies: gst_dep)
+endif
+
+if gst_debug_disabled
+  message('GStreamer debug system is disabled')
+  if cc.has_argument('-Wno-unused')
+    add_project_arguments('-Wno-unused', language: 'c')
+  endif
+  if have_cxx and cxx.has_argument ('-Wno-unused')
+    add_project_arguments('-Wno-unused', language: 'cpp')
+  endif
+else
+  message('GStreamer debug system is enabled')
 endif
 
 presetdir = join_paths(get_option('datadir'), 'gstreamer-' + api_version, 'presets')