Index: contrib/libc++/src/experimental/filesystem/operations.cpp
===================================================================
--- contrib/libc++/src/experimental/filesystem/operations.cpp
+++ contrib/libc++/src/experimental/filesystem/operations.cpp
@@ -548,7 +548,7 @@
 constexpr auto max_time_t = numeric_limits<time_t>::max();
 constexpr auto min_time_t = numeric_limits<time_t>::min();
 
-#if !defined(__LP64__) && defined(__clang__)
+#if !defined(TIME_T_64BIT) && defined(__clang__)
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wtautological-constant-out-of-range-compare"
 #endif
@@ -565,7 +565,7 @@
   }
 }
 #ifndef _LIBCPP_HAS_NO_CXX14_CONSTEXPR
-#if defined(__LP64__)
+#if defined(TIME_T_64BIT)
 static_assert(is_representable({max_seconds, max_nsec}), "");
 static_assert(!is_representable({max_seconds + 1, 0}), "");
 static_assert(!is_representable({max_seconds, max_nsec + 1}), "");
@@ -596,7 +596,7 @@
   return secs.count() >= TLim::min();
 }
 #ifndef _LIBCPP_HAS_NO_CXX14_CONSTEXPR
-#if defined(__LP64__)
+#if defined(TIME_T_64BIT)
 static_assert(is_representable(file_time_type::max()), "");
 static_assert(is_representable(file_time_type::min()), "");
 #else
@@ -622,7 +622,7 @@
   }
 }
 #ifndef _LIBCPP_HAS_NO_CXX14_CONSTEXPR
-#if defined(__LP64__)
+#if defined(TIME_T_64BIT)
 static_assert(convert_timespec({max_seconds, max_nsec}) == file_time_type::max(), "");
 static_assert(convert_timespec({max_seconds, max_nsec - 1}) < file_time_type::max(), "");
 static_assert(convert_timespec({max_seconds - 1, 999999999}) < file_time_type::max(), "");
@@ -634,7 +634,7 @@
 #endif
 #endif
 
-#if !defined(__LP64__) && defined(__clang__)
+#if !defined(TIME_T_64BIT) && defined(__clang__)
 #pragma clang diagnostic pop
 #endif
 
Index: lib/Makefile
===================================================================
--- lib/Makefile
+++ lib/Makefile
@@ -156,10 +156,7 @@
 
 .if ${MK_LIBCPLUSPLUS} != "no"
 _libcxxrt=	libcxxrt
-_libcplusplus=	libc++
-.if ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips"
-_libcplusplus+=	libc++experimental
-.endif
+_libcplusplus=	libc++ libc++experimental
 .endif
 
 SUBDIR.${MK_EFI}+=	libefivar
Index: lib/libc++experimental/Makefile
===================================================================
--- lib/libc++experimental/Makefile
+++ lib/libc++experimental/Makefile
@@ -23,6 +23,9 @@
 CXXFLAGS+=	-nostdlib
 CXXFLAGS+=	-D_LIBCPP_BUILDING_LIBRARY
 CXXFLAGS+=	-DLIBCXXRT
+.if ${MACHINE_CPUARCH} != "i386"
+CXXFLAGS+=	-DTIME_T_64BIT
+.endif
 .if empty(CXXFLAGS:M-std=*)
 CXXFLAGS+=	-std=c++14
 .endif