diff --git a/libs/net/nm/net_udp.c b/libs/net/nm/net_udp.c
index 4d8824078..84f01a3a9 100644
--- a/libs/net/nm/net_udp.c
+++ b/libs/net/nm/net_udp.c
@@ -97,6 +97,12 @@
 #include "netmain.h"
 #include "net_udp.h"
 
+#ifdef HAVE_IN_PKTINFO
+# ifndef SOL_IP		// BSD-based stacks don't define this.
+#  define SOL_IP IPPROTO_IP
+# endif
+#endif
+
 #ifdef _WIN32
 # undef EWOULDBLOCK
 # define EWOULDBLOCK    WSAEWOULDBLOCK
diff --git a/qw/source/master.c b/qw/source/master.c
index 549cd8712..91347ff0a 100644
--- a/qw/source/master.c
+++ b/qw/source/master.c
@@ -70,6 +70,12 @@
 
 #include "qw/protocol.h"
 
+#ifdef HAVE_IN_PKTINFO
+# ifndef SOL_IP		// BSD-based stacks don't define this.
+#  define SOL_IP IPPROTO_IP
+# endif
+#endif
+
 static void __attribute__ ((format (printf, 1, 2)))
 ma_log (const char *fmt, ...);