-dnl Make sure the following libraries work by testing for symbols therein.
-dnl They are automatically added the the variable $LIBS and thus passed into
-dnl the Makefile:
-AC_CHECK_LIB(stdc++, cout)
-
-dnl Make sure all the necessary new-style headers are installed on the system.
-dnl If one of them cannot be found the system is probably not ANSI-conform
-dnl enough so trying the .h-style headers is a waste of time.
-AC_CHECK_HEADERS(iostream vector map string list typeinfo iterator stdexcept algorithm, ,
- AC_MSG_ERROR(need to have ANSI compliant headers))
-AC_CHECK_HEADERS(sstream strstream)
-
-dnl We need to have Bruno Haible's CLN installed (macros are in acinclude.m4):
-GINAC_CHECK_CLN_H
-GINAC_CHECK_LIBCLN
+dnl Make sure all the necessary standard headers are installed on the system.
+AC_CHECK_HEADER(iosfwd, , GINAC_ERROR([The standard <iosfwd> header file could not be found.]))
+AC_CHECK_HEADER(iostream, , GINAC_ERROR([The standard <iostream> header file could not be found.]))
+AC_CHECK_HEADER(vector, , GINAC_ERROR([The standard <vector> header file could not be found.]))
+AC_CHECK_HEADER(list, , GINAC_ERROR([The standard <list> header file could not be found.]))
+AC_CHECK_HEADER(map, , GINAC_ERROR([The standard <map> header file could not be found.]))
+AC_CHECK_HEADER(string, , GINAC_ERROR([The standard <string> header file could not be found.]))
+AC_CHECK_HEADER(sstream, , GINAC_ERROR([The standard <sstream> header file could not be found.]))
+AC_CHECK_HEADER(typeinfo, , GINAC_ERROR([The standard <typeinfo> header file could not be found.]))
+AC_CHECK_HEADER(stdexcept, , GINAC_ERROR([The standard <stdexcept> header file could not be found.]))
+AC_CHECK_HEADER(algorithm, , GINAC_ERROR([The standard <algorithm> header file could not be found.]))
+
+dnl We need to have Bruno Haible's CLN installed.
+dnl (CLN versions >= 1.1.0 must have installed cln.m4 at a visible place,
+dnl which provides this macro):
+AC_PATH_CLN(1.1.0, [
+ LIBS="$LIBS $CLN_LIBS"
+ CPPFLAGS="$CPPFLAGS $CLN_CPPFLAGS"
+], GINAC_ERROR([No suitable installed version of CLN could be found.]))