diff --git a/opt/CMakeLists.txt b/opt/CMakeLists.txt
index a89fdbc..51dfd00 100644
--- a/opt/CMakeLists.txt
+++ b/opt/CMakeLists.txt
@@ -68,7 +68,7 @@ install(TARGETS comm DESTINATION ${MARS_NWE_INSTALL_FULL_LIBEXECDIR})
 install(TARGETS sendm DESTINATION ${MARS_NWE_INSTALL_FULL_LIBEXECDIR})
 install(TARGETS unxcomm DESTINATION ${MARS_NWE_INSTALL_FULL_LIBEXECDIR})
 install(TARGETS unxsendm DESTINATION ${MARS_NWE_INSTALL_FULL_LIBEXECDIR})
-# install(TARGETS xsockrt DESTINATION ${MARS_NWE_INSTALL_FULL_LIBEXECDIR})
+install(TARGETS xsockrt DESTINATION ${MARS_NWE_INSTALL_FULL_LIBEXECDIR})
 
 install(FILES prn DESTINATION ${MARS_NWE_INSTALL_FULL_LIBEXECDIR})
 install(FILES prn-clr DESTINATION ${MARS_NWE_INSTALL_FULL_LIBEXECDIR})
diff --git a/opt/xsockrt.c b/opt/xsockrt.c
index 0471a79..f2ad4e9 100644
--- a/opt/xsockrt.c
+++ b/opt/xsockrt.c
@@ -14,6 +14,7 @@
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/ioctl.h>
+#include <string.h>
 
 
 static int usage(char *prog)