added new test to check whether linking of c++-objcets work

[[Imported from SVN: r3721]]

configure.ac

@@ -13,15 +13,16 @@ AM_CONFIG_HEADER([config.h])
 AC_PROG_CXX
 AC_LANG_PUSH([C++])
 
+# don't build shared libs per default, this is way better for debugging...
+AC_DISABLE_SHARED
+AC_PROG_LIBTOOL
+
 DUNE_CHECK_COMPILER
+DUNE_LINKCXX
 
 # how to create a deprecated warning
 DUNE_CHECKDEPRECATED
 
-# don't build shared libs per default, this is way better for debugging...
-AC_DISABLE_SHARED
-AC_PROG_LIBTOOL
-
 # check for auxiliary tools so that it's not fatal if they're missing
 AC_CHECK_PROGS([DOXYGEN], [doxygen], [true])
 AC_CHECK_PROGS([TEX], [latex], [true])

m4/dune_all.m4

@@ -13,6 +13,7 @@ dnl check for programs
   AC_REQUIRE([AC_PROG_CXX])
   AC_REQUIRE([AC_PROG_CPP])
   AC_REQUIRE([DUNE_CHECK_COMPILER])
+  AC_REQUIRE([DUNE_LINKCXX])
   AC_REQUIRE([DUNE_CHECKDEPRECATED])
   AC_REQUIRE([AC_PROG_INSTALL])
   AC_REQUIRE([AC_PROG_LN_S])

m4/dune_linkcxx.m4

+# $Id$
+# tries to link c++ objects
+
+AC_DEFUN([DUNE_LINKCXX],[
+
+AC_MSG_CHECKING([whether compiling C++ code works])
+AC_COMPILE_IFELSE(
+  AC_LANG_SOURCE(
+    [ #include <iostream>
+      int main (int argc, char** argv) { 
+      std::cout << std::endl;
+      }]),
+  [ AC_MSG_RESULT([yes]);
+    AC_MSG_CHECKING([whether linking C++ objects works]);
+	# link from object file
+	ac_old_link=$ac_link
+	ac_link=`echo "$ac_old_link" | sed "s/conftest\.$ac_ext/conftest\.$ac_objext/"`
+	# disable deletion of object file
+	ac_old_objext=$ac_objext;
+	ac_objext="";
+    AC_LINK_IFELSE([],
+      [ AC_MSG_RESULT([yes])],
+      [ AC_MSG_RESULT([no])
+        AC_MSG_ERROR([Could not link C++ code])])
+	ac_objext=$ac_old_objext;
+    ac_link=$ac_old_link;],
+  [ AC_MSG_RESULT([no])
+    AC_MSG_ERROR([Could not compile C++ code])]
+)
+
+])