+/******************************************************************************
+ * Detect operating systems. This probably needs completing.
+ * The result is that at least one OPENSSL_SYS_os macro should be defined.
+ * However, if none is defined, Unix is assumed.
+ **/
+
+#define OPENSSL_SYS_UNIX
+
+/* ----------------------- Macintosh, before MacOS X ----------------------- */
+#if defined(__MWERKS__) && defined(macintosh) || defined(OPENSSL_SYSNAME_MAC)
+# undef OPENSSL_SYS_UNIX
+# define OPENSSL_SYS_MACINTOSH_CLASSIC
+#endif
+
+/* ---------------------- Microsoft operating systems ---------------------- */
+
+/* The 16 bit environments are pretty straightforward */
+#if defined(OPENSSL_SYSNAME_WIN16) || defined(OPENSSL_SYSNAME_MSDOS)
+# undef OPENSSL_SYS_UNIX
+# define OPENSSL_SYS_MSDOS
+#endif
+#if defined(OPENSSL_SYSNAME_WIN16)
+# undef OPENSSL_SYS_UNIX
+# define OPENSSL_SYS_WIN16
+#endif
+
+/* For 32 bit environment, there seems to be the CygWin environment and then
+ all the others that try to do the same thing Microsoft does... */
+#if defined(__CYGWIN32__) || defined(OPENSSL_SYSNAME_CYGWIN32)
+# undef OPENSSL_SYS_UNIX
+# define OPENSSL_SYS_WIN32_CYGWIN
+#else
+# if defined(_WIN32) || defined(OPENSSL_SYSNAME_WIN32)
+# undef OPENSSL_SYS_UNIX
+# define OPENSSL_SYS_WIN32
+# endif
+# if defined(OPENSSL_SYSNAME_WINNT)
+# undef OPENSSL_SYS_UNIX
+# define OPENSSL_SYS_WINNT
+# endif
+#endif
+
+/* Anything that tries to look like Microsoft is "Windows" */
+#if defined(OPENSSL_SYS_WIN16) || defined(OPENSSL_SYS_WIN32) || defined(OPENSSL_SYS_WINNT)
+# undef OPENSSL_SYS_UNIX
+# define OPENSSL_SYS_WINDOWS
+#endif
+
+/* -------------------------------- OpenVMS -------------------------------- */
+#if defined(__VMS) || defined(VMS) || defined(OPENSSL_SYSNAME_VMS)
+# undef OPENSSL_SYS_UNIX
+# define OPENSSL_SYS_VMS
+# if defined(__DECC)
+# define OPENSSL_SYS_VMS_DECC
+# else
+# define OPENSSL_SYS_VMS_NODECC
+# endif
+#endif
+
+/* --------------------------------- Unix ---------------------------------- */
+#ifdef OPENSSL_SYS_UNIX
+# if defined(linus) || defined(OPENSSL_SYSNAME_LINUX)
+# define OPENSSL_SYS_LINUX
+# endif
+# ifdef OPENSSL_SYSNAME_MPE
+# define OPENSSL_SYS_MPE
+# endif
+# ifdef OPENSSL_SYSNAME_SNI
+# define OPENSSL_SYS_SNI
+# endif
+# ifdef OPENSSL_SYSNAME_ULTRASPARC
+# define OPENSSL_SYS_ULTRASPARC
+# endif
+# ifdef OPENSSL_SYSNAME_NEWS4
+# define OPENSSL_SYS_NEWS4
+# endif
+# ifdef OPENSSL_SYSNAME_MACOSX
+# define OPENSSL_SYS_MACOSX
+# endif
+# if defined(_CRAY) || defined(OPENSSL_SYSNAME_CRAY)
+# define OPENSSL_SYS_CRAY
+# endif
+# if defined(_AIX) || defined(OPENSSL_SYSNAME_AIX)
+# define OPENSSL_SYS_AIX
+# endif
+#endif
+
+/**
+ * That's it for OS-specific stuff
+ *****************************************************************************/
+
+
+/* Specials for I/O an exit */
+#ifdef OPENSSL_SYS_MSDOS