diff --git a/include/boost/endian/detail/intrinsic.hpp b/include/boost/endian/detail/intrinsic.hpp
index c98aec0..8971085 100644
--- a/include/boost/endian/detail/intrinsic.hpp
+++ b/include/boost/endian/detail/intrinsic.hpp
@@ -9,37 +9,46 @@
 #ifndef BOOST_ENDIAN_INTRINSIC_HPP
 #define BOOST_ENDIAN_INTRINSIC_HPP
 
+//  Allow user to force BOOST_ENDIAN_NO_INTRINSICS in case they aren't available for a
+//  particular platform/compiler combination. Please report such platform/compiler
+//  combinations to the Boost mailing list.
+#ifndef BOOST_ENDIAN_NO_INTRINSICS
+
 #ifndef __has_builtin         // Optional of course
   #define __has_builtin(x) 0  // Compatibility with non-clang compilers
 #endif
 
-#if (defined(__clang__) && __has_builtin(__builtin_bswap16)) \
+//  GCC and Clang recent versions provide intrinsic byte swaps via builtins
+#if (defined(__clang__) && __has_builtin(__builtin_bswap32) && __has_builtin(__builtin_bswap64)) \
   || (defined(__GNUC__ ) && \
   (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)))
 # define BOOST_ENDIAN_INTRINSIC_MSG "__builtin_bswap16, etc."
-
 // prior to 4.8, gcc did not provide __builtin_bswap16 on some platforms so we emulate it
 // see http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52624
-# if defined(__clang__) || __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)
+// Clang has a similar problem, but their feature test macros make it easier to detect
+# if (defined(__clang__) && __has_builtin(__builtin_bswap16)) \
+  || (defined(__GNUC__) &&(__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)))
 #   define BOOST_ENDIAN_INTRINSIC_BYTE_SWAP_2(x) __builtin_bswap16(x)
 # else
 #   define BOOST_ENDIAN_INTRINSIC_BYTE_SWAP_2(x) __builtin_bswap32((x) << 16)
 # endif
-
 # define BOOST_ENDIAN_INTRINSIC_BYTE_SWAP_4(x) __builtin_bswap32(x)
 # define BOOST_ENDIAN_INTRINSIC_BYTE_SWAP_8(x) __builtin_bswap64(x)
 
-#elif ((defined __GNUC__ && !defined(__MINGW32__)) || defined(__clang__))
-# define BOOST_ENDIAN_INTRINSIC_MSG "__builtin_bswap_16, etc."
+//  Linux systems provide the byteswap.h header, with 
+#elif defined(__linux__)
+//  don't check for obsolete forms defined(linux) and defined(__linux) on the theory that
+//  compilers that predefine only these are so old that byteswap.h probably isn't present.
+# define BOOST_ENDIAN_INTRINSIC_MSG "byteswap.h bswap_16, etc."
 # include <byteswap.h>
 # define BOOST_ENDIAN_INTRINSIC_BYTE_SWAP_2(x) bswap_16(x)
 # define BOOST_ENDIAN_INTRINSIC_BYTE_SWAP_4(x) bswap_32(x)
 # define BOOST_ENDIAN_INTRINSIC_BYTE_SWAP_8(x) bswap_64(x)
 
-#elif defined _MSC_VER
+#elif defined(_MSC_VER)
 //  Microsoft documents these as being compatible since Windows 95 and specificly
 //  lists runtime library support since Visual Studio 2003 (aka 7.1).
-# define BOOST_ENDIAN_INTRINSIC_MSG "_byteswap_ushort, etc."
+# define BOOST_ENDIAN_INTRINSIC_MSG "cstdlib _byteswap_ushort, etc."
 # include <cstdlib>
 # define BOOST_ENDIAN_INTRINSIC_BYTE_SWAP_2(x) _byteswap_ushort(x)
 # define BOOST_ENDIAN_INTRINSIC_BYTE_SWAP_4(x) _byteswap_ulong(x)
@@ -49,4 +58,5 @@
 # define BOOST_ENDIAN_INTRINSIC_MSG "no byte swap intrinsics"
 #endif
 
-#endif // BOOST_ENDIAN_INTRINSIC_HPP
+#endif  // BOOST_ENDIAN_NO_INTRINSICS
+#endif  // BOOST_ENDIAN_INTRINSIC_HPP
diff --git a/test/intrinsic_test.cpp b/test/intrinsic_test.cpp
index 90a32fb..fc22e12 100644
--- a/test/intrinsic_test.cpp
+++ b/test/intrinsic_test.cpp
@@ -3,10 +3,14 @@
 //  Distributed under the Boost Software License, Version 1.0.
 //  http://www.boost.org/LICENSE_1_0.txt
 
-#include "intrinsic.hpp"
+#include "test.hpp"
 #include <iostream>
 #include <cassert>
-#include <cstdint>
+//#include <cstdint>
+
+typedef unsigned short uint16_t;
+typedef unsigned int uint32_t;
+typedef unsigned long long uint64_t;
 
 int main()
 {