diff --git a/src/ccutil/ccutil.cpp b/src/ccutil/ccutil.cpp
index e33bda47..32e82c75 100644
--- a/src/ccutil/ccutil.cpp
+++ b/src/ccutil/ccutil.cpp
@@ -27,6 +27,11 @@ CCUtil::CCUtil() :
               " whether to adapt to a character", &params_) {
 }
 
+// Destructor.
+// It is defined here, so the compiler can create a single vtable
+// instead of weak vtables in every compilation unit.
+CCUtil::~CCUtil() = default;
+
 CCUtilMutex::CCUtilMutex() {
 #ifdef _WIN32
   mutex_ = CreateMutex(0, FALSE, 0);
diff --git a/src/ccutil/ccutil.h b/src/ccutil/ccutil.h
index fd1b9f83..0cf35ff7 100644
--- a/src/ccutil/ccutil.h
+++ b/src/ccutil/ccutil.h
@@ -51,7 +51,7 @@ class CCUtilMutex {
 class CCUtil {
  public:
   CCUtil();
-  virtual ~CCUtil() = default;
+  virtual ~CCUtil();
 
  public:
   // Read the arguments and set up the data path.