diff --git a/cfg/bsd.cfg b/cfg/bsd.cfg
index 58e8737ee..ce7944b3d 100644
--- a/cfg/bsd.cfg
+++ b/cfg/bsd.cfg
@@ -307,4 +307,11 @@
   <podtype name="ulong" sign="u" stdtype="long"/>
   <!-- https://linux.die.net/man/3/tailq_head -->
   <define name="TAILQ_HEAD(name,type)" value="struct name { type *first; type *last; }"/>
+  <!-- https://man7.org/linux/man-pages/man2/lseek.2.html :
+       Conforming to:
+       SEEK_DATA and SEEK_HOLE are nonstandard extensions also present
+       in Solaris, FreeBSD, and DragonFly BSD; they are proposed for
+       inclusion in the next POSIX revision (Issue 8).-->
+  <define name="SEEK_DATA" value="3"/>
+  <define name="SEEK_HOLE" value="4"/>
 </def>