diff --git a/lib/curl_memory.h b/lib/curl_memory.h
index df64786e8a..41933d6af9 100644
--- a/lib/curl_memory.h
+++ b/lib/curl_memory.h
@@ -69,8 +69,6 @@
 
 #ifdef _WIN32
 #  ifdef UNICODE
-#    undef wcsdup
-#    undef _wcsdup
 #    undef _tcsdup
 #  else
 #    undef _tcsdup
@@ -155,10 +153,6 @@ extern curl_wcsdup_callback Curl_cwcsdup;
 
 #ifdef _WIN32
 #  ifdef UNICODE
-#    undef wcsdup
-#    define wcsdup(ptr) Curl_cwcsdup(ptr)
-#    undef _wcsdup
-#    define _wcsdup(ptr) Curl_cwcsdup(ptr)
 #    undef _tcsdup
 #    define _tcsdup(ptr) Curl_cwcsdup(ptr)
 #  else
diff --git a/lib/memdebug.h b/lib/memdebug.h
index 2038dc34d3..e109e0b20a 100644
--- a/lib/memdebug.h
+++ b/lib/memdebug.h
@@ -142,10 +142,6 @@ CURL_EXTERN ALLOC_FUNC
 
 #ifdef _WIN32
 #  ifdef UNICODE
-#    undef wcsdup
-#    define wcsdup(ptr) curl_dbg_wcsdup(ptr, __LINE__, __FILE__)
-#    undef _wcsdup
-#    define _wcsdup(ptr) curl_dbg_wcsdup(ptr, __LINE__, __FILE__)
 #    undef _tcsdup
 #    define _tcsdup(ptr) curl_dbg_wcsdup(ptr, __LINE__, __FILE__)
 #  else
diff --git a/scripts/checksrc.pl b/scripts/checksrc.pl
index 47ea1cf54a..8dbb3f384e 100755
--- a/scripts/checksrc.pl
+++ b/scripts/checksrc.pl
@@ -65,6 +65,8 @@ my %banfunc = (
     "_tcsncat" => 1,
     "_wcscat" => 1,
     "_wcsncat" => 1,
+    "_wcsdup" => 1,
+    "wcsdup" => 1,
     "LoadLibrary" => 1,
     "LoadLibraryA" => 1,
     "LoadLibraryW" => 1,