render: use internal_features to indicate EGL support

Instead of checking whether the wlr_egl dependencies are available
in the GLES2 code, introduce internal_features['egl'] and check
that field.

When updating the EGL dependency list, we no longer need to update
the GLES2 logic.

meson.build

@@ -96,6 +96,7 @@ features = {
 }
 internal_features = {
 	'xcb-errors': false,
+	'egl': false,
 }
 
 wayland_project_options = ['tests=false', 'documentation=false']

render/gles2/meson.build

@@ -1,6 +1,6 @@
 glesv2 = dependency('glesv2', required: 'gles2' in renderers)
 
-if not (glesv2.found() and egl.found() and gbm.found())
+if not (glesv2.found() and internal_features['egl'])
 	subdir_done()
 endif
 

render/meson.build

@@ -20,6 +20,7 @@ if 'gles2' in renderers or 'auto' in renderers
 	if egl.found() and gbm.found()
 		wlr_deps += [egl, gbm]
 		wlr_files += files('egl.c')
+		internal_features += { 'egl': true }
 	endif
 	subdir('gles2')
 endif