fix pzstd compatibility with mingw

some details changed with introduction of gcc7

contrib/pzstd/Options.cpp

@@ -18,17 +18,6 @@
 #include <thread>
 #include <vector>
 
-#if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(_WIN32) ||     \
-    defined(__CYGWIN__)
-#include <io.h> /* _isatty */
-#define IS_CONSOLE(stdStream) _isatty(_fileno(stdStream))
-#elif defined(_POSIX_C_SOURCE) || defined(_XOPEN_SOURCE) || defined(_POSIX_SOURCE) || (defined(__APPLE__) && defined(__MACH__)) || \
-      defined(__DragonFly__) || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__)  /* https://sourceforge.net/p/predef/wiki/OperatingSystems/ */
-#include <unistd.h> /* isatty */
-#define IS_CONSOLE(stdStream) isatty(fileno(stdStream))
-#else
-#define IS_CONSOLE(stdStream) 0
-#endif
 
 namespace pzstd {