tests: move include of tests/tests.h outside of extern "C"

tests/scripts/test-scripts.cpp

@@ -21,6 +21,8 @@
 
 #include "CppUTest/TestHarness.h"
 
+#include "tests/tests.h"
+
 extern "C"
 {
 #ifndef HAVE_CONFIG_H
@@ -37,8 +39,6 @@ extern "C"
 #include "src/plugins/plugin.h"
 }
 
-#include "tests/tests.h"
-
 struct t_hook *api_hook_print = NULL;
 int api_tests_ok = 0;
 int api_tests_errors = 0;