check.h: remove obsolete header

Since we switched from autotools to Meson in commit
94592c1406, we don't need to include
`config.h` early to properly enable large file support.  Meson passes
the required macros on the compiler command line instead of defining
them in `config.h`.

This means we can include `config.h` at any time, whenever we want to
check its macros, and there are no ordering constraints.

src/mixer/plugins/AlsaMixerPlugin.cxx

@@ -17,7 +17,6 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#include "config.h"
 #include "lib/alsa/NonBlock.hxx"
 #include "mixer/MixerInternal.hxx"
 #include "mixer/Listener.hxx"

src/mixer/plugins/HaikuMixerPlugin.cxx

@@ -20,7 +20,6 @@
  */
 
 
-#include "config.h"
 #include "mixer/MixerInternal.hxx"
 #include "output/plugins/HaikuOutputPlugin.hxx"
 #include "util/Compiler.h"

src/mixer/plugins/NullMixerPlugin.cxx

@@ -17,7 +17,6 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#include "config.h"
 #include "mixer/MixerInternal.hxx"
 
 class NullMixer final : public Mixer {

src/mixer/plugins/OSXMixerPlugin.cxx

@@ -17,7 +17,6 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#include "config.h"
 #include "mixer/MixerInternal.hxx"
 #include "output/plugins/OSXOutputPlugin.hxx"
 

src/mixer/plugins/OssMixerPlugin.cxx

@@ -17,7 +17,6 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#include "config.h"
 #include "mixer/MixerInternal.hxx"
 #include "config/Block.hxx"
 #include "system/FileDescriptor.hxx"

src/mixer/plugins/PulseMixerPlugin.cxx

@@ -17,7 +17,6 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#include "config.h"
 #include "PulseMixerPlugin.hxx"
 #include "lib/pulse/Domain.hxx"
 #include "lib/pulse/LogError.hxx"

src/mixer/plugins/SndioMixerPlugin.cxx

@@ -16,7 +16,6 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#include "config.h"
 #include "mixer/MixerInternal.hxx"
 #include "mixer/Listener.hxx"
 #include "output/plugins/SndioOutputPlugin.hxx"

src/mixer/plugins/SoftwareMixerPlugin.cxx

@@ -17,7 +17,6 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#include "config.h"
 #include "SoftwareMixerPlugin.hxx"
 #include "mixer/MixerInternal.hxx"
 #include "filter/plugins/VolumeFilterPlugin.hxx"

src/mixer/plugins/WinmmMixerPlugin.cxx

@@ -17,7 +17,6 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#include "config.h"
 #include "mixer/MixerInternal.hxx"
 #include "output/OutputAPI.hxx"
 #include "output/plugins/WinmmOutputPlugin.hxx"