On X11, reload DPI on _XSETTINGS_SETTINGS

This also fixes the deadlock when such reload may happen.

Fixes: #3383
Signed-off-by: John Nunley <dev@notgull.net>
Signed-off-by: Kirill Chibisov <contact@kchibisov.com>

src/platform_impl/linux/x11/mod.rs

@@ -10,6 +10,7 @@ mod monitor;
 pub mod util;
 mod window;
 mod xdisplay;
+mod xsettings;
 
 pub(crate) use self::{
     monitor::{MonitorHandle, VideoModeHandle},
@@ -889,6 +890,9 @@ pub enum X11Error {
 
     /// Could not find a matching X11 visual for this visualid
     NoSuchVisual(xproto::Visualid),
+
+    /// Unable to parse xsettings.
+    XsettingsParse(xsettings::ParserError),
 }
 
 impl fmt::Display for X11Error {
@@ -913,6 +917,9 @@ impl fmt::Display for X11Error {
                     visualid
                 )
             }
+            X11Error::XsettingsParse(err) => {
+                write!(f, "Failed to parse xsettings: {:?}", err)
+            }
         }
     }
 }
@@ -981,6 +988,12 @@ impl From<ReplyOrIdError> for X11Error {
     }
 }
 
+impl From<xsettings::ParserError> for X11Error {
+    fn from(value: xsettings::ParserError) -> Self {
+        Self::XsettingsParse(value)
+    }
+}
+
 /// The underlying x11rb connection that we are using.
 type X11rbConnection = x11rb::xcb_ffi::XCBConnection;