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.

1 files changed, 19 insertions, 3 deletions

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