renderer: Explicit sync fixes (#7151)

Enables explicit sync by default for most platforms

`misc:no_direct_scanout` -> `render:direct_scanout`

src/helpers/sync/SyncReleaser.cpp

@@ -0,0 +1,25 @@
+#include "SyncReleaser.hpp"
+#include "SyncTimeline.hpp"
+#include "../../render/OpenGL.hpp"
+
+CSyncReleaser::CSyncReleaser(WP<CSyncTimeline> timeline_, uint64_t point_) : timeline(timeline_), point(point_) {
+    ;
+}
+
+CSyncReleaser::~CSyncReleaser() {
+    if (timeline.expired())
+        return;
+
+    if (sync)
+        timeline->importFromSyncFileFD(point, sync->fd());
+    else
+        timeline->signal(point);
+}
+
+void CSyncReleaser::addReleaseSync(SP<CEGLSync> sync_) {
+    sync = sync_;
+}
+
+void CSyncReleaser::drop() {
+    timeline.reset();
+}