ENH: Test Fortran and C++ in one executable

This extends the Fortran-to-C interface test to add a C++ source file.
The executable can only link with the C++ linker and with the proper
Fortran runtime libraries.  These libraries should be detected by CMake
automatically, so this tests verifies the detection functionality.

Tests/Fortran/CMakeLists.txt

@@ -1,5 +1,5 @@
 cmake_minimum_required (VERSION 2.6)
-project(testf Fortran C)
+project(testf Fortran C CXX)
 message("CTEST_FULL_OUTPUT ")
 set(CMAKE_VERBOSE_MAKEFILE 1)
 message("ENV_FLAGS = $ENV{FFLAGS}")
@@ -30,7 +30,7 @@ function(test_fortran_c_interface_module)
     endif(FORTRAN_C_MODULE_MANGLING_FOUND)
   endif()
   set(FORTRAN_FUNCTIONS ${FORTRAN_FUNCTIONS} my_sub mysub )
-  set(srcs ${srcs} mysub.f foo.c)
+  set(srcs ${srcs} mysub.f foo.c foo.cxx)
   create_fortran_c_interface("F_" FORTRAN_FUNCTIONS 
     "${testf_BINARY_DIR}/foo.h")
   include_directories("${testf_BINARY_DIR}")

Tests/Fortran/foo.c

@@ -1,7 +1,7 @@
 #include "foo.h"
 extern F_test_mod_sub();
 extern F_mysub();
-int main()
+int foo()
 {
   F_mysub();
   F_my_sub();

Tests/Fortran/foo.cxx

@@ -0,0 +1,6 @@
+extern "C" int foo(void);
+int main()
+{
+  delete new int;
+  return foo();
+}