tests/unit: portability fixes for gomodule on ELF

lib/module.c

@@ -164,4 +164,6 @@ void kr_module_unload(struct kr_module *module)
 	if (module->lib && module->lib != RTLD_DEFAULT) {
 		dlclose(module->lib);
 	}
+
+	memset(module, 0, sizeof(struct kr_module));
 }

modules/gostats/gostats.go

@@ -16,7 +16,6 @@ static inline const knot_layer_api_t *_gostats_layer(void)
 */
 import "C"
 import "unsafe"
-import "fmt"
 
 func Api() C.uint32_t {
 	return C.KR_MODULE_API

tests/mock_gomodule.c

@@ -29,7 +29,14 @@ void __go_init_main() {}
  */
 
 /* \note Renamed to mimick Go module. */
-extern uint32_t Api(void) __asm__ ("_main.Api");
+#if defined(__APPLE__)
+    extern uint32_t Api(void) __asm__ ("_main.Api"); /* Mach-O */
+#elif _WIN32
+    #error DLL format is not supported for Golang modules.
+#else
+    extern uint32_t Api(void) __asm__ ("main.Api");  /* ELF */
+#endif
+
 
 uint32_t Api(void)
 {