diff --git a/.build.yml b/.build.yml
index db97f51..b4f1396 100644
--- a/.build.yml
+++ b/.build.yml
@@ -3,6 +3,8 @@
 #
 image: archlinux
 packages:
+  - clang
+  - gcc
   - libevdev
   - libinput
   - libxkbcommon
@@ -17,7 +19,11 @@ sources:
 tasks:
   - setup: |
       cd waybox
-      meson setup build
+      CC=gcc meson setup build-gcc
   - build: |
       cd waybox
-      ninja -C build
+      ninja -C build-gcc
+  - clang: |
+      cd waybox
+      CC=clang meson setup build-clang
+      ninja -C build-clang
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index a8f3ad5..499258d 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -16,12 +16,14 @@ jobs:
         steps:
             - name: packages
               run: |
-                apk add gcc libevdev-dev libinput-dev libxkbcommon-dev libxml2-dev meson musl-dev wayland-dev wayland-protocols wlroots-dev xwayland
+                apk add clang gcc libevdev-dev libinput-dev libxkbcommon-dev libxml2-dev meson musl-dev wayland-dev wayland-protocols wlroots-dev xwayland
             # actions/checkout@v3 clones the repository
             - uses: actions/checkout@v3
-            - name: setup
+            - name: build-gcc
               run: |
-                meson setup build
-            - name: build
+                CC=gcc meson setup build-gcc
+                ninja -C build-gcc
+            - name: build-clang
               run: |
-                ninja -C build
+                CC=clang meson setup build-clang
+                ninja -C build-clang
diff --git a/waybox/xdg_shell.c b/waybox/xdg_shell.c
index 73932bf..2be3c3b 100644
--- a/waybox/xdg_shell.c
+++ b/waybox/xdg_shell.c
@@ -67,7 +67,7 @@ void focus_view(struct wb_view *view, struct wlr_surface *surface) {
 		struct wlr_xdg_surface *previous =
 			wlr_xdg_surface_try_from_wlr_surface(prev_surface);
 #else
-		struct wlr_xdg_surface *previous;
+		struct wlr_xdg_surface *previous = NULL;
 		if (wlr_surface_is_xdg_surface(prev_surface)) {
 			previous = wlr_xdg_surface_from_wlr_surface(prev_surface);
 		}