Merge branch 'missingHeaders' into 'master'

<cstring> is missing in two source files

See merge request OPAL/src!443

ippl/src/Utility/DiscMeta.cpp

@@ -30,6 +30,7 @@
 #include "Utility/IpplInfo.h"
 #include "Utility/Inform.h"
 
+#include <cstring>
 
 ///////////////////////////////////////////////////////////////////////////
 // Constructor: read and parse the given meta file

src/Structure/IpplInfoWrapper.cpp

@@ -4,6 +4,8 @@
 
 #include "Structure/IpplInfoWrapper.h"
 
+#include <cstring>
+
 IpplInfoWrapper::IpplInfoWrapper(const std::string &inputFileName, int infoLevel, int warnLevel, MPI_Comm comm) {
     std::string infoLevelStr = std::to_string(infoLevel);
     std::string warnLevelStr = std::to_string(warnLevel);