diff --git a/src/specfun/fpmath.h b/src/specfun/fpmath.h
index 3b06b7e56b001..505d89f033a1d 100644
--- a/src/specfun/fpmath.h
+++ b/src/specfun/fpmath.h
@@ -38,51 +38,69 @@
 #endif
 #endif
 
-#ifdef __linux
-#include <features.h>
-#include <endian.h>
-#define _LITTLE_ENDIAN  __LITTLE_ENDIAN
-#define _BIG_ENDIAN     __BIG_ENDIAN
-#define _PDP_ENDIAN     __PDP_ENDIAN
-#define _BYTE_ORDER     __BYTE_ORDER
-#endif
-
-#ifdef __APPLE__
-#include <machine/endian.h>
-#define _LITTLE_ENDIAN  LITTLE_ENDIAN
-#define _BIG_ENDIAN     BIG_ENDIAN
-#define _PDP_ENDIAN     PDP_ENDIAN
-#define _BYTE_ORDER     BYTE_ORDER
-#endif
-
-#ifdef __FreeBSD__
-#include <machine/endian.h>
-#endif
+// We need to find out the byte ordering of the system.
+//
+// This will be stored in the following macros:
+// _FPMATH_LITTLE_ENDIAN: An arbitrary constant
+// _FPMATH_BIG_ENDIAN: An arbitrary constant
+// _FPMATH_BYTE_ORDER: Either _FPMATH_LITTLE_ENDIAN or _FPMATH_BIG_ENDIAN
 
-#ifdef _WIN32
-#define _LITTLE_ENDIAN 1234
-#define _BIG_ENDIAN    4321
-#define _PDP_ENDIAN    3412
-#define _BYTE_ORDER       _LITTLE_ENDIAN
-#define _FLOAT_WORD_ORDER _LITTLE_ENDIAN
-#define LITTLE_ENDIAN  _LITTLE_ENDIAN
-#define BIG_ENDIAN     _BIG_ENDIAN
-#define PDP_ENDIAN     _PDP_ENDIAN
-#define BYTE_ORDER     _BYTE_ORDER
+// The GNU preprocessor defines a few things by itself
+// See http://gcc.gnu.org/onlinedocs/cpp/Common-Predefined-Macros.html#Common-Predefined-Macros
+#if defined(__ORDER_LITTLE_ENDIAN__) && defined(__ORDER_BIG_ENDIAN__) &&  defined(__BYTE_ORDER__)
+#  define _FPMATH_BIG_ENDIAN    __ORDER_BIG_ENDIAN__
+#  define _FPMATH_LITTLE_ENDIAN __ORDER_LITTLE_ENDIAN__
+#  define _FPMATH_BYTE_ORDER    __BYTE_ORDER__
+// If not defined by the preprocessor, let us try to do it ourselves.
+// Linux
+#elif defined(__linux)
+#  include <features.h>
+#  include <endian.h>
+#  define _FPMATH_LITTLE_ENDIAN  __LITTLE_ENDIAN
+#  define _FPMATH_BIG_ENDIAN     __BIG_ENDIAN
+#  define _FPMATH_BYTE_ORDER     __BYTE_ORDER
+// OSX
+#elif defined(__APPLE__)
+#  include <machine/endian.h>
+#  define _FPMATH_LITTLE_ENDIAN  LITTLE_ENDIAN
+#  define _FPMATH_BIG_ENDIAN     BIG_ENDIAN
+#  define _FPMATH_BYTE_ORDER     BYTE_ORDER
+// FreeBSD
+#elif defined(__FreeBSD__)
+#  include <machine/endian.h>
+#  define _FPMATH_LITTLE_ENDIAN  _LITTLE_ENDIAN
+#  define _FPMATH_BIG_ENDIAN     _BIG_ENDIAN
+#  define _FPMATH_BYTE_ORDER     _BYTE_ORDER
+// Windows
+#elif defined(_WIN32)
+#  define _FPMATH_LITTLE_ENDIAN 1234
+#  define _FPMATH_BIG_ENDIAN    4321
+#  define _FPMATH_BYTE_ORDER    _FPMATH_LITTLE_ENDIAN
+// Solaris
+#elif defined(__sun)
+#  define _FPMATH_LITTLE_ENDIAN 1234
+#  define _FPMATH_BIG_ENDIAN    4321
+#  include <sys/isa_defs.h>
+#  ifdef _LITTLE_ENDIAN
+#    define _FPMATH_BYTE_ORDER _FPMATH_LITTLE_ENDIAN
+#  endif
+#  ifdef _BIG_ENDIAN
+#    define _FPMATH_BYTE_ORDER _FPMATH_BIG_ENDIAN
+#  endif
 #endif
 
 #ifndef _IEEE_WORD_ORDER
-#define	_IEEE_WORD_ORDER	_BYTE_ORDER
+#define	_IEEE_WORD_ORDER	_FPMATH_BYTE_ORDER
 #endif
 
 union IEEEf2bits {
 	float	f;
 	struct {
-#if _BYTE_ORDER == _LITTLE_ENDIAN
+#if _FPMATH_BYTE_ORDER == _FPMATH_LITTLE_ENDIAN
 		unsigned int	man	:23;
 		unsigned int	exp	:8;
 		unsigned int	sign	:1;
-#else /* _BIG_ENDIAN */
+#else /* _FPMATH_BIG_ENDIAN */
 		unsigned int	sign	:1;
 		unsigned int	exp	:8;
 		unsigned int	man	:23;
@@ -96,17 +114,17 @@ union IEEEf2bits {
 union IEEEd2bits {
 	double	d;
 	struct {
-#if _BYTE_ORDER == _LITTLE_ENDIAN
-#if _IEEE_WORD_ORDER == _LITTLE_ENDIAN
+#if _FPMATH_BYTE_ORDER == _FPMATH_LITTLE_ENDIAN
+#if _IEEE_WORD_ORDER == _FPMATH_LITTLE_ENDIAN
 		unsigned int	manl	:32;
 #endif
 		unsigned int	manh	:20;
 		unsigned int	exp	:11;
 		unsigned int	sign	:1;
-#if _IEEE_WORD_ORDER == _BIG_ENDIAN
+#if _IEEE_WORD_ORDER == _FPMATH_BIG_ENDIAN
 		unsigned int	manl	:32;
 #endif
-#else /* _BIG_ENDIAN */
+#else /* _FPMATH_BIG_ENDIAN */
 		unsigned int	sign	:1;
 		unsigned int	exp	:11;
 		unsigned int	manh	:20;