diff --git a/meson.build b/meson.build
index 8221e89f..c54c39ef 100644
--- a/meson.build
+++ b/meson.build
@@ -16,12 +16,9 @@ config_h.set_quoted('PACKAGE', meson.project_name())
 config_h.set_quoted('PACKAGE_VERSION', meson.project_version())
 
 cc_args = []
-if host_machine.system() != 'freebsd'
+if not host_machine.system().contains('bsd')
 	cc_args += ['-D_POSIX_C_SOURCE=200809L']
 endif
-if host_machine.system() == 'netbsd'
-	cc_args += ['-D_NETBSD_SOURCE']
-endif
 add_project_arguments(cc_args, language: 'c')
 
 compiler_flags = [