diff --git a/meson.build b/meson.build
index bf266e5f9..f59d29b30 100644
--- a/meson.build
+++ b/meson.build
@@ -36,7 +36,7 @@ gdk_pixbuf     = dependency('gdk-pixbuf-2.0', required: false)
 pixman         = dependency('pixman-1')
 libcap         = dependency('libcap')
 libinput       = dependency('libinput', version: '>=1.6.0')
-libpam         = cc.find_library('libpam')
+libpam         = cc.find_library('pam')
 math           = cc.find_library('m')
 rt             = cc.find_library('rt')
 git = find_program('git', required: false)
diff --git a/protocols/wlr-layer-shell-unstable-v1.xml b/protocols/wlr-layer-shell-unstable-v1.xml
index 3181c0bbf..6a5d5d35f 100644
--- a/protocols/wlr-layer-shell-unstable-v1.xml
+++ b/protocols/wlr-layer-shell-unstable-v1.xml
@@ -47,12 +47,16 @@
         or manipulate a buffer prior to the first layer_surface.configure call
         must also be treated as errors.
 
+        You may pass NULL for output to allow the compositor to decide which
+        output to use. Generally this will be the one that the user most
+        recently interacted with.
+
         Clients can specify a namespace that defines the purpose of the layer
         surface.
       </description>
       <arg name="id" type="new_id" interface="zwlr_layer_surface_v1"/>
       <arg name="surface" type="object" interface="wl_surface"/>
-      <arg name="output" type="object" interface="wl_output"/>
+      <arg name="output" type="object" interface="wl_output" allow-null="true"/>
       <arg name="layer" type="uint" enum="layer" summary="layer to add this surface to"/>
       <arg name="namespace" type="string" summary="namespace for the layer surface"/>
     </request>
diff --git a/swaybg/main.c b/swaybg/main.c
index 679b8c205..5b6c378c3 100644
--- a/swaybg/main.c
+++ b/swaybg/main.c
@@ -113,7 +113,7 @@ static void layer_surface_closed(void *data,
 	state->run_display = false;
 }
 
-struct zwlr_layer_surface_v1_listener layer_surface_listener = {
+static const struct zwlr_layer_surface_v1_listener layer_surface_listener = {
 	.configure = layer_surface_configure,
 	.closed = layer_surface_closed,
 };
@@ -141,7 +141,7 @@ static void output_scale(void *data, struct wl_output *output, int32_t factor) {
 	}
 }
 
-struct wl_output_listener output_listener = {
+static const struct wl_output_listener output_listener = {
 	.geometry = output_geometry,
 	.mode = output_mode,
 	.done = output_done,
@@ -203,7 +203,8 @@ int main(int argc, const char **argv) {
 		return 1;
 	}
 
-	assert(state.display = wl_display_connect(NULL));
+	state.display = wl_display_connect(NULL);
+	assert(state.display);
 
 	struct wl_registry *registry = wl_display_get_registry(state.display);
 	wl_registry_add_listener(registry, &registry_listener, &state);
@@ -213,9 +214,11 @@ int main(int argc, const char **argv) {
 	// Second roundtrip to get output properties
 	wl_display_roundtrip(state.display);
 
-	assert(state.surface = wl_compositor_create_surface(state.compositor));
+	state.surface = wl_compositor_create_surface(state.compositor);
+	assert(state.surface);
 
-	assert(state.input_region = wl_compositor_create_region(state.compositor));
+	state.input_region = wl_compositor_create_region(state.compositor);
+	assert(state.input_region);
 	wl_surface_set_input_region(state.surface, state.input_region);
 
 	state.layer_surface = zwlr_layer_shell_v1_get_layer_surface(