diff --git a/gdbstub/meson.build b/gdbstub/meson.build
index bd5c5cd..cdb4d28 100644
--- a/gdbstub/meson.build
+++ b/gdbstub/meson.build
@@ -20,11 +20,13 @@
 libgdb_user = static_library('gdb_user',
                              gdb_user_ss.sources() + genh,
                              name_suffix: 'fa',
-                             c_args: '-DCONFIG_USER_ONLY')
+                             c_args: '-DCONFIG_USER_ONLY',
+                             build_by_default: have_user)
 
 libgdb_softmmu = static_library('gdb_softmmu',
                                 gdb_softmmu_ss.sources() + genh,
-                                name_suffix: 'fa')
+                                name_suffix: 'fa',
+                                build_by_default: have_system)
 
 gdb_user = declare_dependency(link_whole: libgdb_user)
 user_ss.add(gdb_user)