meson: add option to disable LDAP

Add a meson option that can be used to disable LDAP support.  This will
allow the Yocto recipe to reduce the libraries pulled in for configs
that do not use LDAP.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ida0b7f7062dd4672812eb25825d4c4bebd571901
diff --git a/meson.options b/meson.options
index 44551ad..95df809 100644
--- a/meson.options
+++ b/meson.options
@@ -1,4 +1,7 @@
 option('tests', type: 'feature', description: 'Build tests', value: 'enabled')
+
+option('ldap', type: 'feature', description: 'Enable LDAP support')
+
 option(
     'root_user_mgmt',
     type: 'feature',