diff --git a/.pick_status.json b/.pick_status.json
index dc1f141cfb2..b136d4924ab 100644
--- a/.pick_status.json
+++ b/.pick_status.json
@@ -931,7 +931,7 @@
         "description": "meson: build with _ISOC11_SOURCE on OpenBSD",
         "nominated": true,
         "nomination_type": 1,
-        "resolution": 0,
+        "resolution": 1,
         "master_sha": null,
         "because_sha": "e3a8013de8ca854d21225be00f123ccf63f9060f"
     },
diff --git a/meson.build b/meson.build
index 291ae424850..4ee86381bbb 100644
--- a/meson.build
+++ b/meson.build
@@ -958,6 +958,8 @@ elif host_machine.system() == 'windows'
   else
     pre_args += ['-D__MSVCRT_VERSION__=0x0700']
   endif
+elif host_machine.system() == 'openbsd'
+  pre_args += '-D_ISOC11_SOURCE'
 endif
 
 # Check for generic C arguments