gamescope mouse sensitivity <0 dead range fix

mouse_sense_fix.patch

--- a/src/wlserver.cpp
+++ b/src/wlserver.cpp
@@ -2336,6 +2336,8 @@ static bool wlserver_apply_constraint( double *dx, double *dy )
 	return true;
 }
 
+static double rem_x = 0.0;
+static double rem_y = 0.0;
 void wlserver_mousemotion( double dx, double dy, uint32_t time )
 {
 	assert( wlserver_is_lock_held() );
@@ -2343,6 +2345,14 @@ void wlserver_mousemotion( double dx, double dy, uint32_t time )
 	dx *= g_mouseSensitivity;
 	dy *= g_mouseSensitivity;
 
+	dx += rem_x;
+	dy += rem_y;
+	rem_x = fmod(dx,  1.0);
+	rem_y = fmod(dy,  1.0);
+	dx -= rem_x;
+	dy -= rem_y;
+	if (abs(dx) <= 0 && abs(dy) <= 0) return;
+
 	wlserver_perform_rel_pointer_motion( dx, dy );
 
 	if ( !wlserver_apply_constraint( &dx, &dy ) )

adapted from ValveSoftware/gamescope#1521 (comment)