XERCESC-2161 - Missing message file in dist

git-svn-id: https://svn.apache.org/repos/asf/xerces/c/trunk@1872117 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/Makefile.am b/src/Makefile.am
index 461f342..e7dcf3b 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -62,6 +62,7 @@
         xercesc/util/Xerces_autoconf_config.hpp.cmake.in \
         xercesc/util/XercesVersion.hpp.cmake.in \
         xercesc/util/version.rc.cmake.in \
+        xercesc/util/MsgLoaders/MsgCatalog/XercesMessages_en_US.Msg \
         xercesc/util/MsgLoaders/ICU/resources
 
 libxerces_c_la_LIBADD = ${LTLIBOBJS}