Kernel: Add definitions for SO_SNDLOWAT and SO_RCVLOWAT

Author: https://github.com/gunnarbeutner
Commit: https://github.com/SerenityOS/serenity/commit/de6048b7d3
Pull-request: https://github.com/SerenityOS/serenity/pull/15764

Kernel/API/POSIX/sys/socket.h

@@ -118,6 +118,8 @@ enum {
     SO_ACCEPTCONN,
     SO_DONTROUTE,
     SO_OOBINLINE,
+    SO_SNDLOWAT,
+    SO_RCVLOWAT,
 };
 #define SO_RCVTIMEO SO_RCVTIMEO
 #define SO_SNDTIMEO SO_SNDTIMEO
@@ -136,6 +138,8 @@ enum {
 #define SO_ACCEPTCONN SO_ACCEPTCONN
 #define SO_DONTROUTE SO_DONTROUTE
 #define SO_OOBINLINE SO_OOBINLINE
+#define SO_SNDLOWAT SO_SNDLOWAT
+#define SO_RCVLOWAT SO_RCVLOWAT
 
 enum {
     SCM_TIMESTAMP,