diff --git a/.ci/build.sh b/.ci/build.sh
index 3ac28eb8a..60917f43e 100644
--- a/.ci/build.sh
+++ b/.ci/build.sh
@@ -590,7 +590,7 @@ else
 	esac
 
 	# Establish general dependencies.
-	pkgs="cmake ninja-build pkg-config git wget p7zip-full wayland-protocols tar gzip file appstream"
+	pkgs="cmake ninja-build pkg-config git wget p7zip-full extra-cmake-modules wayland-protocols tar gzip file appstream"
 	if [ "$(dpkg --print-architecture)" = "$arch_deb" ]
 	then
 		pkgs="$pkgs build-essential"
@@ -608,7 +608,7 @@ else
 	fi
 
 	# Establish architecture-specific dependencies we don't want listed on the readme...
-	pkgs="$pkgs linux-libc-dev:$arch_deb extra-cmake-modules:$arch_deb qttools5-dev:$arch_deb qtbase5-private-dev:$arch_deb"
+	pkgs="$pkgs linux-libc-dev:$arch_deb qttools5-dev:$arch_deb qtbase5-private-dev:$arch_deb"
 
 	# ...and the ones we do want listed. Non-dev packages fill missing spots on the list.
 	libpkgs=""
diff --git a/src/qt/qt_platform.cpp b/src/qt/qt_platform.cpp
index eff022b3d..89ead7acd 100644
--- a/src/qt/qt_platform.cpp
+++ b/src/qt/qt_platform.cpp
@@ -54,6 +54,7 @@ QElapsedTimer elapsed_timer;
 
 static std::atomic_int blitmx_contention = 0;
 static std::recursive_mutex blitmx;
+static thread_local std::unique_lock blit_lock { blitmx, std::defer_lock };
 
 class CharPointer {
 public:
@@ -468,17 +469,17 @@ void dynld_close(void *handle)
 void startblit()
 {
     blitmx_contention++;
-    if (blitmx.try_lock()) {
+    if (blit_lock.try_lock()) {
         return;
     }
 
-    blitmx.lock();
+    blit_lock.lock();
 }
 
 void endblit()
 {
     blitmx_contention--;
-    blitmx.unlock();
+    blit_lock.unlock();
     if (blitmx_contention > 0) {
         // a deadlock has been observed on linux when toggling via video_toggle_option
         // because the mutex is typically unfair on linux