Expose High DPI support configuration flag

The High DPI support is enabled by default, so that the renderer use the
full definition of High DPI screens.

However, there are still mouse coordinates problems on some MacOS having
High DPI support (but not all), so expose a way to disable it.

app/meson.build

@@ -80,6 +80,9 @@ conf.set('DEFAULT_BIT_RATE', '8000000')  # 8Mbps
 # SKIP_FRAMES improves latency at the cost of framerate
 conf.set('SKIP_FRAMES', get_option('skip_frames'))
 
+# enable High DPI support
+conf.set('HIDPI_SUPPORT', get_option('hidpi_support'))
+
 configure_file(configuration: conf, output: 'config.h')
 
 executable('scrcpy', src, dependencies: dependencies, install: true)