Merge topic 'create-test-source-list-extern'

78983cb85e create_test_source_list: declare functions as `extern`

Acked-by: Kitware Robot <[email protected]>
Acked-by: buildbot <[email protected]>
Merge-request: !10274

Source/cmCreateTestSourceList.cxx

@@ -93,7 +93,8 @@ bool cmCreateTestSourceList(std::vector<std::string> const& args,
       tests_func_name.end();
     tests_func_name.push_back(func_name);
     if (!already_declared) {
-      forwardDeclareCode += cmStrCat("int ", func_name, "(int, char*[]);\n");
+      forwardDeclareCode +=
+        cmStrCat("extern int ", func_name, "(int, char*[]);\n");
     }
   }