diff --git a/libstdc++-v3/src/c++20/tzdb.cc b/libstdc++-v3/src/c++20/tzdb.cc
index 890a4c53e2d442169329076794c3f36c8befb2dc..639d1c440ba16eb62ba5c835cdac9af3c5deea84 100644
--- a/libstdc++-v3/src/c++20/tzdb.cc
+++ b/libstdc++-v3/src/c++20/tzdb.cc
@@ -70,8 +70,9 @@ namespace __gnu_cxx
 #else
   [[gnu::weak]] const char* zoneinfo_dir_override();
 
-#if defined(__APPLE__) || defined(__hpux__)
-  // Need a weak definition for Mach-O.
+#if defined(__APPLE__) || defined(__hpux__) \
+  || (defined(__VXWORKS__) && !defined(__RTP__))
+  // Need a weak definition for Mach-O et al.
   [[gnu::weak]] const char* zoneinfo_dir_override()
   {
 #ifdef _GLIBCXX_ZONEINFO_DIR