Docu update.

ChangeLog

@@ -9,7 +9,7 @@
 
 2017-05-16  Uwe Schulzweida
 
-	* Renamed all .c files to .cc, code needs to be compiled with a C++ compiler!!!
+	* Renamed all .c files to .cc, code needs to be compiled with an ISO C++11 compiler!!!
 
 2017-05-16  Uwe Schulzweida
 

doc/tex/install.tex

@@ -2,7 +2,7 @@
 
 This section describes how to build {\CDO} from the sources on a UNIX system.
 {\CDO} uses the GNU configure and build system for compilation.
-The only requirement is a working ANSI C99 compiler.
+The only requirement is a working ISO C++11 and ANSI C99 compiler.
 
 %First go to the \href{http://www.mpimet.mpg.de/cdo/download.html}{\texttt{download}} page
 %(\texttt{http://www.mpimet.mpg.de/\\,cdo/download.html}) to get the latest distribution,

src/cdo.cc

@@ -930,6 +930,9 @@ void print_system_info()
 #if defined(_OPENMP)
   fprintf(stderr, "OPENMP VERSION      = %d\n", _OPENMP);
 #endif
+#if defined(__cplusplus)
+  fprintf(stderr, "__cplusplus         = %ld\n", __cplusplus);
+#endif
 #if defined(__GNUC__)
   fprintf(stderr, "GNUC VERSION        = %d\n", __GNUC__);
 #endif