diff --git a/CMakeLists.txt b/CMakeLists.txt
index 56763122..5b4cccd6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -319,6 +319,7 @@ if(CMAKE_SYSTEM_NAME STREQUAL "OS/390")
   list(APPEND uv_defines _OPEN_MSGQ_EXT)
   list(APPEND uv_defines _OPEN_SYS_FILE_EXT)
   list(APPEND uv_defines _OPEN_SYS_IF_EXT)
+  list(APPEND uv_defines _OPEN_SYS_SOCK_EXT3)
   list(APPEND uv_defines _OPEN_SYS_SOCK_IPV6)
   list(APPEND uv_defines _UNIX03_SOURCE)
   list(APPEND uv_defines _UNIX03_THREADS)
diff --git a/Makefile.am b/Makefile.am
index 7d380c51..099b0efb 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -519,6 +519,7 @@ libuv_la_CFLAGS += -D_UNIX03_THREADS \
                    -D_XOPEN_SOURCE_EXTENDED \
                    -D_ALL_SOURCE \
                    -D_LARGE_TIME_API \
+                   -D_OPEN_SYS_SOCK_EXT3 \
                    -D_OPEN_SYS_SOCK_IPV6 \
                    -D_OPEN_SYS_FILE_EXT \
                    -DUV_PLATFORM_SEM_T=int \
diff --git a/uv.gyp b/uv.gyp
index 46de9b76..75a6d978 100644
--- a/uv.gyp
+++ b/uv.gyp
@@ -20,6 +20,7 @@
           '_UNIX03_SOURCE',
           '_UNIX03_WITHDRAWN',
           '_OPEN_SYS_IF_EXT',
+          '_OPEN_SYS_SOCK_EXT3',
           '_OPEN_SYS_SOCK_IPV6',
           '_OPEN_MSGQ_EXT',
           '_XOPEN_SOURCE_EXTENDED',