diff --git a/libcxx/include/__support/android/locale_bionic.h b/libcxx/include/__support/android/locale_bionic.h
--- a/libcxx/include/__support/android/locale_bionic.h
+++ b/libcxx/include/__support/android/locale_bionic.h
@@ -58,6 +58,10 @@
   return ::strtol(__nptr, __endptr, __base);
 }
 
+inline _LIBCPP_HIDE_FROM_ABI_C unsigned long strtoul_l(const char* __nptr, char** __endptr, int __base, locale_t) {
+  return ::strtoul(__nptr, __endptr, __base);
+}
+
 #if defined(__cplusplus)
 }
 #endif
diff --git a/libcxx/include/__support/musl/xlocale.h b/libcxx/include/__support/musl/xlocale.h
--- a/libcxx/include/__support/musl/xlocale.h
+++ b/libcxx/include/__support/musl/xlocale.h
@@ -24,10 +24,19 @@
 extern "C" {
 #endif
 
+inline _LIBCPP_HIDE_FROM_ABI_C long strtol_l(const char* __nptr, char** __endptr, int __base, locale_t) {
+  return ::strtol(__nptr, __endptr, __base);
+}
+
 inline _LIBCPP_HIDE_FROM_ABI_C long long strtoll_l(const char* __nptr, char** __endptr, int __base, locale_t) {
   return ::strtoll(__nptr, __endptr, __base);
 }
 
+inline _LIBCPP_HIDE_FROM_ABI_C unsigned long
+strtoul_l(const char* __nptr, char** __endptr, int __base, locale_t) {
+  return ::strtoul(__nptr, __endptr, __base);
+}
+
 inline _LIBCPP_HIDE_FROM_ABI_C unsigned long long
 strtoull_l(const char* __nptr, char** __endptr, int __base, locale_t) {
   return ::strtoull(__nptr, __endptr, __base);
diff --git a/libcxx/include/__support/openbsd/xlocale.h b/libcxx/include/__support/openbsd/xlocale.h
--- a/libcxx/include/__support/openbsd/xlocale.h
+++ b/libcxx/include/__support/openbsd/xlocale.h
@@ -16,20 +16,4 @@
 #include <ctype.h>
 #include <cwctype>
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-inline _LIBCPP_HIDE_FROM_ABI_C long strtol_l(const char* __nptr, char** __endptr, int __base, locale_t) {
-  return ::strtol(__nptr, __endptr, __base);
-}
-
-inline _LIBCPP_HIDE_FROM_ABI_C unsigned long strtoul_l(const char* __nptr, char** __endptr, int __base, locale_t) {
-  return ::strtoul(__nptr, __endptr, __base);
-}
-
-#ifdef __cplusplus
-}
-#endif
-
 #endif
diff --git a/libcxx/include/__support/win32/locale_win32.h b/libcxx/include/__support/win32/locale_win32.h
--- a/libcxx/include/__support/win32/locale_win32.h
+++ b/libcxx/include/__support/win32/locale_win32.h
@@ -214,7 +214,9 @@
 
 // the *_l functions are prefixed on Windows, only available for msvcr80+, VS2005+
 #define mbtowc_l _mbtowc_l
+#define strtol_l _strtol_l
 #define strtoll_l _strtoi64_l
+#define strtoul_l _strtoul_l
 #define strtoull_l _strtoui64_l
 #define strtod_l _strtod_l
 #if defined(_LIBCPP_MSVCRT)
diff --git a/libcxx/include/__support/xlocale/__strtonum_fallback.h b/libcxx/include/__support/xlocale/__strtonum_fallback.h
--- a/libcxx/include/__support/xlocale/__strtonum_fallback.h
+++ b/libcxx/include/__support/xlocale/__strtonum_fallback.h
@@ -38,10 +38,19 @@
   return ::strtold(__nptr, __endptr);
 }
 
+inline _LIBCPP_HIDE_FROM_ABI_C long strtol_l(const char* __nptr, char** __endptr, int __base, locale_t) {
+  return ::strtol(__nptr, __endptr, __base);
+}
+
 inline _LIBCPP_HIDE_FROM_ABI_C long long strtoll_l(const char* __nptr, char** __endptr, int __base, locale_t) {
   return ::strtoll(__nptr, __endptr, __base);
 }
 
+inline _LIBCPP_HIDE_FROM_ABI_C unsigned long
+strtoul_l(const char* __nptr, char** __endptr, int __base, locale_t) {
+  return ::strtoul(__nptr, __endptr, __base);
+}
+
 inline _LIBCPP_HIDE_FROM_ABI_C unsigned long long
 strtoull_l(const char* __nptr, char** __endptr, int __base, locale_t) {
   return ::strtoull(__nptr, __endptr, __base);