diff --git a/meson.build b/meson.build
index 724ac27..2307f24 100644
--- a/meson.build
+++ b/meson.build
@@ -6,6 +6,11 @@ project('pkgconf', 'c',
 
 cc = meson.get_compiler('c')
 
+add_project_arguments(
+  '-D_BSD_SOURCE',
+  '-D_DEFAULT_SOURCE',
+  language : 'c',
+)
 
 cdata = configuration_data()