Move allocator stuff into new directory

Add render/allocator/ and include/render/allocator/ to hold
everything allocator-related.

include/render/allocator/drm_dumb.h

@@ -0,0 +1,37 @@
+#ifndef RENDER_ALLOCATOR_DRM_DUMB_H
+#define RENDER_ALLOCATOR_DRM_DUMB_H
+
+#include <wlr/render/dmabuf.h>
+#include <wlr/types/wlr_buffer.h>
+#include "render/allocator/allocator.h"
+
+struct wlr_drm_dumb_buffer {
+	struct wlr_buffer base;
+	struct wl_list link; // wlr_drm_dumb_allocator::buffers
+
+	int drm_fd; // -1 if the allocator has been destroyed
+	struct wlr_dmabuf_attributes dmabuf;
+
+	uint32_t format;
+	uint32_t handle;
+	uint32_t stride;
+	uint32_t width, height;
+
+	uint64_t size;
+	void *data;
+};
+
+struct wlr_drm_dumb_allocator {
+	struct wlr_allocator base;
+	struct wl_list buffers; // wlr_drm_dumb_buffer::link
+	int drm_fd;
+};
+
+/**
+ * Creates a new drm dumb allocator from a DRM FD.
+ *
+ * Does not take ownership over the FD.
+ */
+struct wlr_allocator *wlr_drm_dumb_allocator_create(int fd);
+
+#endif