diff --git a/libcxx/include/__bsd_locale_defaults.h b/libcxx/include/__bsd_locale_defaults.h
--- a/libcxx/include/__bsd_locale_defaults.h
+++ b/libcxx/include/__bsd_locale_defaults.h
@@ -14,23 +14,79 @@
 #ifndef _LIBCPP___BSD_LOCALE_DEFAULTS_H
 #define _LIBCPP___BSD_LOCALE_DEFAULTS_H
 
+#include <__config>
+#include <__utility/declval.h>
+#include <__utility/forward.h>
+#include <cstddef>
+#include <cwchar>
+
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
-#define __libcpp_mb_cur_max_l(loc)                          MB_CUR_MAX_L(loc)
-#define __libcpp_btowc_l(ch, loc)                           btowc_l(ch, loc)
-#define __libcpp_wctob_l(wch, loc)                          wctob_l(wch, loc)
-#define __libcpp_wcsnrtombs_l(dst, src, nwc, len, ps, loc)  wcsnrtombs_l(dst, src, nwc, len, ps, loc)
-#define __libcpp_wcrtomb_l(src, wc, ps, loc)                wcrtomb_l(src, wc, ps, loc)
-#define __libcpp_mbsnrtowcs_l(dst, src, nms, len, ps, loc)  mbsnrtowcs_l(dst, src, nms, len, ps, loc)
-#define __libcpp_mbrtowc_l(pwc, s, n, ps, l)                mbrtowc_l(pwc, s, n, ps, l)
-#define __libcpp_mbtowc_l(pwc, pmb, max, l)                 mbtowc_l(pwc, pmb, max, l)
-#define __libcpp_mbrlen_l(s, n, ps, l)                      mbrlen_l(s, n, ps, l)
-#define __libcpp_localeconv_l(l)                            localeconv_l(l)
-#define __libcpp_mbsrtowcs_l(dest, src, len, ps, l)         mbsrtowcs_l(dest, src, len, ps, l)
-#define __libcpp_snprintf_l(...)                            snprintf_l(__VA_ARGS__)
-#define __libcpp_asprintf_l(...)                            asprintf_l(__VA_ARGS__)
-#define __libcpp_sscanf_l(...)                              sscanf_l(__VA_ARGS__)
+inline _LIBCPP_HIDE_FROM_ABI decltype(MB_CUR_MAX_L(std::declval<locale_t>()))
+__libcpp_mb_cur_max_l(locale_t __loc) _NOEXCEPT {
+  return MB_CUR_MAX_L(__loc);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI wint_t __libcpp_btowc_l(int __c, locale_t __loc) _NOEXCEPT {
+  return ::btowc_l(__c, __loc);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI int __libcpp_wctob_l(wint_t __c, locale_t __loc) _NOEXCEPT {
+  return ::wctob_l(__c, __loc);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI size_t __libcpp_wcsnrtombs_l(
+    char* __dest, const wchar_t** __src, size_t __nwc, size_t __len, mbstate_t* __ps, locale_t __loc) _NOEXCEPT {
+  return ::wcsnrtombs_l(__dest, __src, __nwc, __len, __ps, __loc);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI size_t
+__libcpp_wcrtomb_l(char* __src, wchar_t __wc, mbstate_t* __ps, locale_t __loc) _NOEXCEPT {
+  return ::wcrtomb_l(__src, __wc, __ps, __loc);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI size_t __libcpp_mbsnrtowcs_l(
+    wchar_t* __dest, const char** __src, size_t __nms, size_t __len, mbstate_t* __ps, locale_t __loc) _NOEXCEPT {
+  return ::mbsnrtowcs_l(__dest, __src, __nms, __len, __ps, __loc);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI size_t
+__libcpp_mbrtowc_l(wchar_t* __pwc, const char* __s, size_t __n, mbstate_t* __ps, locale_t __loc) _NOEXCEPT {
+  return ::mbrtowc_l(__pwc, __s, __n, __ps, __loc);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI int
+__libcpp_mbtowc_l(wchar_t* __pwc, const char* __s, size_t __n, locale_t __loc) _NOEXCEPT {
+  return ::mbtowc_l(__pwc, __s, __n, __loc);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI size_t
+__libcpp_mbrlen_l(const char* __s, size_t __n, mbstate_t* __ps, locale_t __loc) _NOEXCEPT {
+  return ::mbrlen_l(__s, __n, __ps, __loc);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI lconv* __libcpp_localeconv_l(locale_t __loc) _NOEXCEPT { return ::localeconv_l(__loc); }
+
+inline _LIBCPP_HIDE_FROM_ABI size_t
+__libcpp_mbsrtowcs_l(wchar_t* __dest, const char** __src, size_t __len, mbstate_t* __ps, locale_t __loc) _NOEXCEPT {
+  return ::mbsrtowcs_l(__dest, __src, __len, __ps, __loc);
+}
+
+template <class... _Args>
+int __libcpp_snprintf_l(char* __str, size_t __size, locale_t __loc, const char* __format, _Args&&... __args) _NOEXCEPT {
+  return ::snprintf_l(__str, __size, __loc, __format, std::forward<_Args>(__args)...);
+}
+
+template <class... _Args>
+int __libcpp_asprintf_l(char** __ret, locale_t __loc, const char* __format, _Args&&... __args) _NOEXCEPT {
+  return ::asprintf_l(__ret, __loc, __format, std::forward<_Args>(__args)...);
+}
+
+template <class... _Args>
+int __libcpp_sscanf_l(const char* __str, locale_t __loc, const char* __format, _Args&&... __args) _NOEXCEPT {
+  return ::sscanf_l(__str, __loc, __format, std::forward<_Args>(__args)...);
+}
 
 #endif // _LIBCPP___BSD_LOCALE_DEFAULTS_H