Resolve RTSD-256

Fixed bug that caused modelsim warning "multiple occurences of ini variable ..." for unb2b. Done by deleting duplicate library clause name entries in removed_libs.

Closes RTSD-256

core/modelsim_config

@@ -240,12 +240,15 @@ class ModelsimConfig(hdl_libraries_wizard.HdlLibrariesWizard):
                     lib_work = os.path.join(lib_dir, 'work')
                     fp.write('%s = %s\n' % (lib_clause, lib_work))
 
-                # . not used vendor technology libs are not compiled but are mapped to work to avoid compile error when mentioned in the LIBRARY clause
-                for removed_lib in sorted(self.removed_libs):
-                    # Only map library to work if it does not exist as a libraries that is used. It might be the case that two libraries with the same
-                    # name exist for multiple technologies causing it to show up in the "use_lib_clause_names" list as well as in the "removed_libs" list.
-                    if self.removed_libs[removed_lib]['hdl_library_clause_name'] not in use_lib_clause_names:
-                        fp.write('%s = work\n' % self.removed_libs[removed_lib]['hdl_library_clause_name'])
+                # Not used vendor technology libs are not compiled but are mapped to work to avoid compile error when mentioned in the LIBRARY clause
+                # . get the lib clause names of removed libraries and delete duplicates.
+                removed_lib_clause_names = [self.removed_libs[l]['hdl_library_clause_name'] for l in self.removed_libs]
+                removed_lib_clause_names = list(dict.fromkeys(removed_lib_clause_names))
+                # . Only map library to work if it does not exist as a libraries that is used. It might be the case that two libraries with the same
+                #   name exist for multiple technologies causing it to show up in the "use_lib_clause_names" list as well as in the "removed_libs" list.
+                for removed_lib in sorted(removed_lib_clause_names):
+                    if removed_lib not in use_lib_clause_names:
+                        fp.write('%s = work\n' % removed_lib)
 
                 # . unavailable used libs are not compiled but are mapped to work to avoid compile error when mentioned in the LIBRARY clause
                 for unavailable_use_name in sorted(self.unavailable_use_libs):