diff --git a/meson.build b/meson.build
index f03fe0b..43861aa 100644
--- a/meson.build
+++ b/meson.build
@@ -8,7 +8,7 @@ project(
 )
 
 add_project_arguments(
-    ['-D_POSIX_C_SOURCE=200809L', '-Wno-unused-parameter'],
+    ['-D_XOPEN_SOURCE=700', '-Wno-unused-parameter'],
     language: 'c',
 )
 
@@ -47,25 +47,25 @@ wp_viewporter = [
 ]
 
 layer_shell = [
-    proto_c.process('wlr-layer-shell-unstable-v1.xml'),
-    proto_h.process('wlr-layer-shell-unstable-v1.xml'),
+    proto_c.process('protocols/wlr-layer-shell-unstable-v1.xml'),
+    proto_h.process('protocols/wlr-layer-shell-unstable-v1.xml'),
 ]
 
 screencopy = [
-    proto_c.process('wlr-screencopy-unstable-v1.xml'),
-    proto_h.process('wlr-screencopy-unstable-v1.xml'),
+    proto_c.process('protocols/wlr-screencopy-unstable-v1.xml'),
+    proto_h.process('protocols/wlr-screencopy-unstable-v1.xml'),
 ]
 
 executable(
     meson.project_name(),
     install: true,
     sources: [
-        'array.c',
-        'buffer.c',
-        'capture.c',
-        'image.c',
-        'main.c',
-        'overlay.c',
+        'src/array.c',
+        'src/buffer.c',
+        'src/capture.c',
+        'src/image.c',
+        'src/main.c',
+        'src/overlay.c',
         xdg_shell,
         wp_viewporter,
         layer_shell,
@@ -83,7 +83,7 @@ if unity.found()
         'array',
         executable(
             'array.test',
-            sources: ['array.c', 'array.test.c'],
+            sources: ['src/array.c', 'src/array.test.c'],
             dependencies: [unity_dep],
         ),
     )
@@ -92,7 +92,7 @@ if unity.found()
         'image',
         executable(
             'image.test',
-            sources: ['image.c', 'image.test.c'],
+            sources: ['src/image.c', 'src/image.test.c'],
             dependencies: [math, pixman, unity_dep],
         ),
     )
diff --git a/wlr-layer-shell-unstable-v1.xml b/protocols/wlr-layer-shell-unstable-v1.xml
similarity index 100%
rename from wlr-layer-shell-unstable-v1.xml
rename to protocols/wlr-layer-shell-unstable-v1.xml
diff --git a/wlr-screencopy-unstable-v1.xml b/protocols/wlr-screencopy-unstable-v1.xml
similarity index 100%
rename from wlr-screencopy-unstable-v1.xml
rename to protocols/wlr-screencopy-unstable-v1.xml
diff --git a/array.c b/src/array.c
similarity index 100%
rename from array.c
rename to src/array.c
diff --git a/array.h b/src/array.h
similarity index 61%
rename from array.h
rename to src/array.h
index d9ee0f4..8a8d2ca 100644
--- a/array.h
+++ b/src/array.h
@@ -16,16 +16,18 @@ void *array_grow_if_needed(void *array, size_t element_size,
                            size_t new_capacity);
 
 #define array_push(array, element)                                       \
-  {                                                                      \
+  do {                                                                   \
     (array) = array_grow_if_needed((array), sizeof(*array),              \
                                    array_length(array) + 1);             \
     (array)[((struct array_header *)(array) - 1)->length++] = (element); \
-  };
+  } while (0)
 
-#define array_free(array)                     \
-  if (array) {                                \
-    free((struct array_header *)(array) - 1); \
-    (array) = NULL;                           \
-  }
+#define array_free(array)                       \
+  do {                                          \
+    if (array) {                                \
+      free((struct array_header *)(array) - 1); \
+      (array) = NULL;                           \
+    }                                           \
+  } while (0)
 
 #endif
diff --git a/array.test.c b/src/array.test.c
similarity index 100%
rename from array.test.c
rename to src/array.test.c
diff --git a/buffer.c b/src/buffer.c
similarity index 100%
rename from buffer.c
rename to src/buffer.c
diff --git a/buffer.h b/src/buffer.h
similarity index 100%
rename from buffer.h
rename to src/buffer.h
diff --git a/capture.c b/src/capture.c
similarity index 100%
rename from capture.c
rename to src/capture.c
diff --git a/capture.h b/src/capture.h
similarity index 100%
rename from capture.h
rename to src/capture.h
diff --git a/image.c b/src/image.c
similarity index 94%
rename from image.c
rename to src/image.c
index a0bec7c..2201c85 100644
--- a/image.c
+++ b/src/image.c
@@ -1,9 +1,8 @@
 #include "image.h"
+#include <math.h>
 #include <pixman.h>
 #include <stdint.h>
 
-#define PI 3.14159265358979323846
-
 pixman_image_t *
 image_revert_wl_output_transform(pixman_image_t *src,
                                  enum wl_output_transform wl_output_transform) {
@@ -25,7 +24,7 @@ image_revert_wl_output_transform(pixman_image_t *src,
   pixman_f_transform_translate(&f_transform, NULL, -(double)src_width / 2,
                                -(double)src_height / 2);
 
-  double rotation_radians = PI * (wl_output_transform % 4) / 2.0;
+  double rotation_radians = M_PI * (wl_output_transform % 4) / 2.0;
   pixman_f_transform_rotate(&f_transform, NULL, round(cos(rotation_radians)),
                             round(sin(rotation_radians)));
 
diff --git a/image.h b/src/image.h
similarity index 100%
rename from image.h
rename to src/image.h
diff --git a/image.test.c b/src/image.test.c
similarity index 100%
rename from image.test.c
rename to src/image.test.c
diff --git a/main.c b/src/main.c
similarity index 100%
rename from main.c
rename to src/main.c
diff --git a/overlay.c b/src/overlay.c
similarity index 100%
rename from overlay.c
rename to src/overlay.c
diff --git a/overlay.h b/src/overlay.h
similarity index 100%
rename from overlay.h
rename to src/overlay.h