diff --git a/libcxx/src/algorithm.cpp b/libcxx/src/algorithm.cpp
--- a/libcxx/src/algorithm.cpp
+++ b/libcxx/src/algorithm.cpp
@@ -8,7 +8,12 @@
 
 #include "algorithm"
 #include "random"
+#ifndef _LIBCPP_HAS_NO_THREADS
 #include "mutex"
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "pthread")
+#endif
+#endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
diff --git a/libcxx/src/chrono.cpp b/libcxx/src/chrono.cpp
--- a/libcxx/src/chrono.cpp
+++ b/libcxx/src/chrono.cpp
@@ -37,6 +37,10 @@
 #endif
 #endif
 
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "rt")
+#endif
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 namespace chrono
diff --git a/libcxx/src/condition_variable.cpp b/libcxx/src/condition_variable.cpp
--- a/libcxx/src/condition_variable.cpp
+++ b/libcxx/src/condition_variable.cpp
@@ -15,6 +15,10 @@
 #include "system_error"
 #include "__undef_macros"
 
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "pthread")
+#endif
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 condition_variable::~condition_variable()
diff --git a/libcxx/src/debug.cpp b/libcxx/src/debug.cpp
--- a/libcxx/src/debug.cpp
+++ b/libcxx/src/debug.cpp
@@ -13,7 +13,12 @@
 #include "string"
 #include "cstdio"
 #include "__hash_table"
+#ifndef _LIBCPP_HAS_NO_THREADS
 #include "mutex"
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "pthread")
+#endif
+#endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
diff --git a/libcxx/src/experimental/memory_resource.cpp b/libcxx/src/experimental/memory_resource.cpp
--- a/libcxx/src/experimental/memory_resource.cpp
+++ b/libcxx/src/experimental/memory_resource.cpp
@@ -12,6 +12,9 @@
 #include "atomic"
 #elif !defined(_LIBCPP_HAS_NO_THREADS)
 #include "mutex"
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "pthread")
+#endif
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
diff --git a/libcxx/src/filesystem/operations.cpp b/libcxx/src/filesystem/operations.cpp
--- a/libcxx/src/filesystem/operations.cpp
+++ b/libcxx/src/filesystem/operations.cpp
@@ -44,6 +44,10 @@
 #include <sys/time.h> // for gettimeofday and timeval
 #endif                // !defined(CLOCK_REALTIME)
 
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "rt")
+#endif
+
 #if defined(_LIBCPP_COMPILER_GCC)
 #if _GNUC_VER < 500
 #pragma GCC diagnostic ignored "-Wmissing-field-initializers"
diff --git a/libcxx/src/memory.cpp b/libcxx/src/memory.cpp
--- a/libcxx/src/memory.cpp
+++ b/libcxx/src/memory.cpp
@@ -10,6 +10,9 @@
 #ifndef _LIBCPP_HAS_NO_THREADS
 #include "mutex"
 #include "thread"
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "pthread")
+#endif
 #endif
 #include "include/atomic_support.h"
 
diff --git a/libcxx/src/mutex.cpp b/libcxx/src/mutex.cpp
--- a/libcxx/src/mutex.cpp
+++ b/libcxx/src/mutex.cpp
@@ -12,6 +12,12 @@
 #include "include/atomic_support.h"
 #include "__undef_macros"
 
+#ifndef _LIBCPP_HAS_NO_THREADS
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "pthread")
+#endif
+#endif
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 #ifndef _LIBCPP_HAS_NO_THREADS
 
diff --git a/libcxx/src/shared_mutex.cpp b/libcxx/src/shared_mutex.cpp
--- a/libcxx/src/shared_mutex.cpp
+++ b/libcxx/src/shared_mutex.cpp
@@ -10,6 +10,9 @@
 #ifndef _LIBCPP_HAS_NO_THREADS
 
 #include "shared_mutex"
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "pthread")
+#endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
diff --git a/libcxx/src/thread.cpp b/libcxx/src/thread.cpp
--- a/libcxx/src/thread.cpp
+++ b/libcxx/src/thread.cpp
@@ -35,6 +35,10 @@
 #include <windows.h>
 #endif
 
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "pthread")
+#endif
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 thread::~thread()
diff --git a/libunwind/src/AddressSpace.hpp b/libunwind/src/AddressSpace.hpp
--- a/libunwind/src/AddressSpace.hpp
+++ b/libunwind/src/AddressSpace.hpp
@@ -27,6 +27,9 @@
 
 #if _LIBUNWIND_USE_DLADDR
 #include <dlfcn.h>
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "dl")
+#endif
 #endif
 
 #ifdef __APPLE__