Fix include in test_document.cpp when building against libc++

tests/test_document.cpp

@@ -22,12 +22,11 @@
 #	include <stdexcept>
 #endif
 
-#ifdef __MINGW32__
-#	include <io.h> // for unlink in C++0x mode
-#endif
-
-#if defined(__CELLOS_LV2__) || defined(ANDROID) || defined(_GLIBCXX_HAVE_UNISTD_H) || defined(__APPLE__)
-#	include <unistd.h> // for unlink
+// for unlink
+#ifdef _WIN32
+#	include <io.h>
+#else
+#	include <unistd.h>
 #endif
 
 using namespace pugi;