ENH: check for compile flags and add back c flag to unix generator

Tests/ComplexOneConfig/Executable/CMakeLists.txt

@@ -1,6 +1,7 @@
 #
 # Create exe. 
 #
+SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DTEST_CXX_FLAGS")
 SET_SOURCE_FILES_PROPERTIES(complex 
                             COMPILE_FLAGS "-DFILE_HAS_EXTRA_COMPILE_FLAGS")
 ADD_EXECUTABLE(complex complex)

Tests/ComplexOneConfig/Executable/complex.cxx

@@ -132,7 +132,10 @@ int main()
     {
     cmPassed("Call to file2 function returned 1.");
     }
-
+#ifndef TEST_CXX_FLAGS
+  cmFailed("CMake CMAKE_CXX_FLAGS is not being passed to the compiler!");
+#else
+  cmPassed("CMake CMAKE_CXX_FLAGS is being passed to the compiler.");
   // ----------------------------------------------------------------------
   // Test ADD_DEFINITIONS