Index: include/__config
===================================================================
--- include/__config
+++ include/__config
@@ -1225,7 +1225,8 @@
 #  endif
 #endif
 
-#if __has_attribute(require_constant_initialization)
+#if __has_attribute(require_constant_initialization) &&                        \
+    !(defined(_LIBCPP_HAS_THREAD_API_PTHREAD) && defined(__MINGW32__))
 #  define _LIBCPP_SAFE_STATIC __attribute__((__require_constant_initialization__))
 #else
 #  define _LIBCPP_SAFE_STATIC
Index: lib/CMakeLists.txt
===================================================================
--- lib/CMakeLists.txt
+++ lib/CMakeLists.txt
@@ -4,7 +4,13 @@
 # FIXME: Don't use glob here
 file(GLOB LIBCXX_SOURCES ../src/*.cpp)
 if(WIN32)
-  file(GLOB LIBCXX_WIN32_SOURCES ../src/support/win32/*.cpp)
+  set(LIBCXX_WIN32_SOURCES
+    ../src/support/win32/locale_win32.cpp
+    ../src/support/win32/support.cpp
+  )
+  if(LIBCXX_HAS_WIN32_THREAD_API)
+    list(APPEND LIBCXX_WIN32_SOURCES ../src/support/win32/thread_win32.cpp)
+  endif()
   list(APPEND LIBCXX_SOURCES ${LIBCXX_WIN32_SOURCES})
 elseif("${CMAKE_SYSTEM_NAME}" STREQUAL "SunOS")
   file(GLOB LIBCXX_SOLARIS_SOURCES ../src/support/solaris/*.cpp)