diff --git a/CMakeLists.txt b/CMakeLists.txt
index d05dcf2d..a0c2e926 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -174,8 +174,6 @@ target_link_libraries(boost_context
     Boost::pool
     Boost::predef
     Boost::smart_ptr
-  PRIVATE
-    Boost::thread
 )
 
 target_compile_definitions(boost_context
diff --git a/build/Jamfile.v2 b/build/Jamfile.v2
index eb83bbb7..9a81210a 100644
--- a/build/Jamfile.v2
+++ b/build/Jamfile.v2
@@ -850,26 +850,13 @@ alias impl_sources
 
 explicit impl_sources ;
 
-obj cxx11_hdr_mutex_check : ../build/cxx11_hdr_mutex.cpp ;
-explicit cxx11_hdr_mutex_check ;
-local cxx11_mutex = [ check-target-builds
-      cxx11_hdr_mutex_check "C++11 mutex"
-    :
-    : <library>/boost/thread//boost_thread
-  ] ;
-
 alias stack_traits_sources
     : windows/stack_traits.cpp
     : <target-os>windows
-    :
-    : $(cxx11_mutex)
     ;
 
 alias stack_traits_sources
     : posix/stack_traits.cpp
-    :
-    :
-    : $(cxx11_mutex)
     ;
 
 explicit stack_traits_sources ;
diff --git a/build/cxx11_hdr_mutex.cpp b/build/cxx11_hdr_mutex.cpp
deleted file mode 100644
index d16a7a15..00000000
--- a/build/cxx11_hdr_mutex.cpp
+++ /dev/null
@@ -1,10 +0,0 @@
-//          Copyright Kohei Takahashi 2016.
-// Distributed under the Boost Software License, Version 1.0.
-//    (See accompanying file LICENSE_1_0.txt or copy at
-//          http://www.boost.org/LICENSE_1_0.txt)
-
-#include <boost/config.hpp>
-
-#ifdef BOOST_NO_CXX11_HDR_MUTEX
-#error "C++11 <mutex> is not available."
-#endif
diff --git a/src/posix/stack_traits.cpp b/src/posix/stack_traits.cpp
index a1086f78..4dd1829f 100644
--- a/src/posix/stack_traits.cpp
+++ b/src/posix/stack_traits.cpp
@@ -20,11 +20,6 @@ extern "C" {
 
 #include <boost/assert.hpp>
 #include <boost/config.hpp>
-#if defined(BOOST_NO_CXX11_HDR_MUTEX)
-# include <boost/thread.hpp>
-#else
-# include <mutex>
-#endif
 
 #if !defined (SIGSTKSZ)
 # define SIGSTKSZ (32768) // 32kb minimum allowable stack
@@ -42,37 +37,20 @@ extern "C" {
 
 namespace {
 
-void pagesize_( std::size_t * size) BOOST_NOEXCEPT_OR_NOTHROW {
+std::size_t pagesize() BOOST_NOEXCEPT_OR_NOTHROW {
     // conform to POSIX.1-2001
-    * size = ::sysconf( _SC_PAGESIZE);
+    return ::sysconf( _SC_PAGESIZE);
 }
 
-void stacksize_limit_( rlimit * limit) BOOST_NOEXCEPT_OR_NOTHROW {
+rlim_t stacksize_limit_() BOOST_NOEXCEPT_OR_NOTHROW {
+    rlimit limit;
     // conforming to POSIX.1-2001
-    ::getrlimit( RLIMIT_STACK, limit);
+    ::getrlimit( RLIMIT_STACK, & limit);
+    return limit.rlim_max;
 }
 
-std::size_t pagesize() BOOST_NOEXCEPT_OR_NOTHROW {
-    static std::size_t size = 0;
-#if defined(BOOST_NO_CXX11_HDR_MUTEX)
-    static boost::once_flag flag = BOOST_ONCE_INIT;
-    boost::call_once( flag, pagesize_, & size);
-#else
-    static std::once_flag flag;
-    std::call_once( flag, pagesize_, & size);
-#endif
-    return size;
-}
-
-rlimit stacksize_limit() BOOST_NOEXCEPT_OR_NOTHROW {
-    static rlimit limit;
-#if defined(BOOST_NO_CXX11_HDR_MUTEX)
-    static boost::once_flag flag = BOOST_ONCE_INIT;
-    boost::call_once( flag, stacksize_limit_, & limit);
-#else
-    static std::once_flag flag;
-    std::call_once( flag, stacksize_limit_, & limit);
-#endif
+rlim_t stacksize_limit() BOOST_NOEXCEPT_OR_NOTHROW {
+    static rlim_t limit = stacksize_limit_();
     return limit;
 }
 
@@ -83,12 +61,13 @@ namespace context {
 
 bool
 stack_traits::is_unbounded() BOOST_NOEXCEPT_OR_NOTHROW {
-    return RLIM_INFINITY == stacksize_limit().rlim_max;
+    return RLIM_INFINITY == stacksize_limit();
 }
 
 std::size_t
 stack_traits::page_size() BOOST_NOEXCEPT_OR_NOTHROW {
-    return pagesize();
+    static std::size_t size = pagesize();
+    return size;
 }
 
 std::size_t
@@ -104,7 +83,7 @@ stack_traits::minimum_size() BOOST_NOEXCEPT_OR_NOTHROW {
 std::size_t
 stack_traits::maximum_size() BOOST_NOEXCEPT_OR_NOTHROW {
     BOOST_ASSERT( ! is_unbounded() );
-    return static_cast< std::size_t >( stacksize_limit().rlim_max);
+    return static_cast< std::size_t >( stacksize_limit() );
 }
 
 }}
diff --git a/src/windows/stack_traits.cpp b/src/windows/stack_traits.cpp
index 14016b1b..4edada09 100644
--- a/src/windows/stack_traits.cpp
+++ b/src/windows/stack_traits.cpp
@@ -20,11 +20,6 @@ extern "C" {
 
 #include <boost/assert.hpp>
 #include <boost/context/detail/config.hpp>
-#if defined(BOOST_NO_CXX11_HDR_MUTEX)
-# include <boost/thread.hpp>
-#else
-# include <mutex>
-#endif
 
 #include <boost/context/stack_context.hpp>
 
@@ -48,24 +43,10 @@ extern "C" {
 
 namespace {
 
-void system_info_( SYSTEM_INFO * si) BOOST_NOEXCEPT_OR_NOTHROW {
-    ::GetSystemInfo( si);
-}
-
-SYSTEM_INFO system_info() BOOST_NOEXCEPT_OR_NOTHROW {
-    static SYSTEM_INFO si;
-#if defined(BOOST_NO_CXX11_HDR_MUTEX)
-    static boost::once_flag flag = BOOST_ONCE_INIT;
-    boost::call_once( flag, static_cast< void(*)( SYSTEM_INFO *) >( system_info_), & si);
-#else
-    static std::once_flag flag;
-    std::call_once( flag, static_cast< void(*)( SYSTEM_INFO *) >( system_info_), & si);
-#endif
-    return si;
-}
-
 std::size_t pagesize() BOOST_NOEXCEPT_OR_NOTHROW {
-    return static_cast< std::size_t >( system_info().dwPageSize);
+    SYSTEM_INFO si;
+    ::GetSystemInfo(&si);
+    return static_cast< std::size_t >( si.dwPageSize );
 }
 
 }
@@ -84,7 +65,8 @@ stack_traits::is_unbounded() BOOST_NOEXCEPT_OR_NOTHROW {
 BOOST_CONTEXT_DECL
 std::size_t
 stack_traits::page_size() BOOST_NOEXCEPT_OR_NOTHROW {
-    return pagesize();
+    static std::size_t size = pagesize();
+    return size;
 }
 
 BOOST_CONTEXT_DECL