remove bundled muparser gcc 9 warning

I am not sure I understand if the default assignment operator does the
right thing here, but this avoids the warning and shouldn't change
functionality.

diff --git a/bundled/muparser_v2_2_4/include/muParserCallback.h b/bundled/muparser_v2_2_4/include/muParserCallback.h
index ef32b4989e34b92c82ad06daf50014022781657c..0beb8c5d4f3d153301e0bdbb46fbc6df914c5654 100644 (file)
--- a/bundled/muparser_v2_2_4/include/muParserCallback.h
+++ b/bundled/muparser_v2_2_4/include/muParserCallback.h
@@ -81,6 +81,9 @@ public:
     ParserCallback(strfun_type3 a_pFun, bool a_bAllowOpti);\r
     ParserCallback();\r
     ParserCallback(const ParserCallback &a_Fun);\r
+\r
+    // deall.II: added the following line to remove Wdeprecated-copy warnings:\r
+    constexpr ParserCallback& operator=(const ParserCallback&)=default;\r
     \r
     ParserCallback* Clone() const;\r
 \r