diff --git a/expat/xmltok/xmldef.h b/expat/xmltok/xmldef.h
index 253bf63b07fc..59a85f0f74a8 100644
--- a/expat/xmltok/xmldef.h
+++ b/expat/xmltok/xmldef.h
@@ -53,5 +53,7 @@ particular environments. */
 #endif /* MOZILLA */
 
 // Enable Unicode string processing in expat
+#ifndef XP_UNIX
 #define XML_UNICODE_WCHAR_T
-#define XML_UNICODE
\ No newline at end of file
+#endif
+#define XML_UNICODE
diff --git a/parser/expat/lib/xmldef.h b/parser/expat/lib/xmldef.h
index 253bf63b07fc..59a85f0f74a8 100644
--- a/parser/expat/lib/xmldef.h
+++ b/parser/expat/lib/xmldef.h
@@ -53,5 +53,7 @@ particular environments. */
 #endif /* MOZILLA */
 
 // Enable Unicode string processing in expat
+#ifndef XP_UNIX
 #define XML_UNICODE_WCHAR_T
-#define XML_UNICODE
\ No newline at end of file
+#endif
+#define XML_UNICODE