build: make GBM optional

Now that the DRM backend no longer depends on GBM, we can make it
optional. The GLES2 renderer still depends on it because of our EGL
device selection.

This is useful for compositors with their own renderers, and for
compositors using the Vulkan renderer.

4 files changed, 30 insertions, 7 deletions

diff --git a/render/allocator/allocator.c b/render/allocator/allocator.c
index 83e836ae..6b96e023 100644
--- a/render/allocator/allocator.c
+++ b/render/allocator/allocator.c
@@ -3,6 +3,7 @@
 #include <fcntl.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <wlr/config.h>
 #include <wlr/interfaces/wlr_buffer.h>
 #include <wlr/render/allocator.h>
 #include <wlr/util/log.h>
@@ -11,10 +12,13 @@
 #include "backend/backend.h"
 #include "render/allocator/allocator.h"
 #include "render/allocator/drm_dumb.h"
-#include "render/allocator/gbm.h"
 #include "render/allocator/shm.h"
 #include "render/wlr_renderer.h"
 
+#if WLR_HAS_GBM_ALLOCATOR
+#include "render/allocator/gbm.h"
+#endif
+
 void wlr_allocator_init(struct wlr_allocator *alloc,
 		const struct wlr_allocator_interface *impl, uint32_t buffer_caps) {
 	assert(impl && impl->destroy && impl->create_buffer);
@@ -94,6 +98,8 @@ struct wlr_allocator *allocator_autocreate_with_drm_fd(
 	uint32_t renderer_caps = renderer_get_render_buffer_caps(renderer);
 
 	struct wlr_allocator *alloc = NULL;
+
+#if WLR_HAS_GBM_ALLOCATOR
 	uint32_t gbm_caps = WLR_BUFFER_CAP_DMABUF;
 	if ((backend_caps & gbm_caps) && (renderer_caps & gbm_caps)
 			&& drm_fd >= 0) {
@@ -108,6 +114,7 @@ struct wlr_allocator *allocator_autocreate_with_drm_fd(
 		close(gbm_fd);
 		wlr_log(WLR_DEBUG, "Failed to create gbm allocator");
 	}
+#endif
 
 	uint32_t shm_caps = WLR_BUFFER_CAP_SHM | WLR_BUFFER_CAP_DATA_PTR;
 	if ((backend_caps & shm_caps) && (renderer_caps & shm_caps)) {
diff --git a/render/allocator/meson.build b/render/allocator/meson.build
index db17ccb2..f8e452df 100644
--- a/render/allocator/meson.build
+++ b/render/allocator/meson.build
@@ -1,9 +1,25 @@
+allocators = get_option('allocators')
+if 'auto' in allocators and get_option('auto_features').enabled()
+	allocators = ['gbm']
+elif 'auto' in renderers and get_option('auto_features').disabled()
+	allocators = []
+endif
+
 wlr_files += files(
 	'allocator.c',
-	'gbm.c',
 	'shm.c',
 	'drm_dumb.c',
 )
 
-has = cc.has_function('gbm_bo_get_fd_for_plane', dependencies: [gbm])
-add_project_arguments('-DHAS_GBM_BO_GET_FD_FOR_PLANE=@0@'.format(has.to_int()), language: 'c')
+gbm = disabler()
+if 'gbm' in allocators or 'auto' in allocators
+	gbm = dependency('gbm', version: '>=17.1.0', required: 'gbm' in allocators)
+endif
+if gbm.found()
+	wlr_files += files('gbm.c')
+	wlr_deps += gbm
+	features += { 'gbm-allocator': true }
+
+	has = cc.has_function('gbm_bo_get_fd_for_plane', dependencies: [gbm])
+	add_project_arguments('-DHAS_GBM_BO_GET_FD_FOR_PLANE=@0@'.format(has.to_int()), language: 'c')
+endif
diff --git a/render/gles2/renderer.c b/render/gles2/renderer.c
index 5ffd6f85..e7bfe0e0 100644
--- a/render/gles2/renderer.c
+++ b/render/gles2/renderer.c
@@ -1,6 +1,5 @@
 #include <assert.h>
 #include <drm_fourcc.h>
-#include <gbm.h>
 #include <GLES2/gl2.h>
 #include <GLES2/gl2ext.h>
 #include <stdint.h>
diff --git a/render/meson.build b/render/meson.build
index a1289ede..2bdcced8 100644
--- a/render/meson.build
+++ b/render/meson.build
@@ -16,8 +16,9 @@ wlr_files += files(
 
 if 'gles2' in renderers or 'auto' in renderers
 	egl = dependency('egl', required: 'gles2' in renderers)
-	if egl.found()
-		wlr_deps += egl
+	gbm = dependency('gbm', required: 'gles2' in renderers)
+	if egl.found() and gbm.found()
+		wlr_deps += [egl, gbm]
 		wlr_files += files('egl.c')
 	endif
 	subdir('gles2')