-dnl Make sure all the necessary new-style headers are installed on the system.
-dnl If one of them cannot be found the system is probably not ANSI-conform
-dnl enough so trying the .h-style headers is a waste of time.
-AC_CHECK_HEADERS(iostream vector map string list typeinfo iterator stdexcept algorithm, ,
- AC_MSG_ERROR(need to have ANSI compliant headers))
-AC_CHECK_HEADERS(sstream strstream)
+dnl Make sure all the necessary standard headers are installed on the system.
+AC_CHECK_HEADER(iosfwd, , GINAC_ERROR([The standard <iosfwd> header file could not be found.]))
+AC_CHECK_HEADER(iostream, , GINAC_ERROR([The standard <iostream> header file could not be found.]))
+AC_CHECK_HEADER(vector, , GINAC_ERROR([The standard <vector> header file could not be found.]))
+AC_CHECK_HEADER(list, , GINAC_ERROR([The standard <list> header file could not be found.]))
+AC_CHECK_HEADER(map, , GINAC_ERROR([The standard <map> header file could not be found.]))
+AC_CHECK_HEADER(string, , GINAC_ERROR([The standard <string> header file could not be found.]))
+AC_CHECK_HEADER(sstream, , GINAC_ERROR([The standard <sstream> header file could not be found.]))
+AC_CHECK_HEADER(typeinfo, , GINAC_ERROR([The standard <typeinfo> header file could not be found.]))
+AC_CHECK_HEADER(stdexcept, , GINAC_ERROR([The standard <stdexcept> header file could not be found.]))
+AC_CHECK_HEADER(algorithm, , GINAC_ERROR([The standard <algorithm> header file could not be found.]))