+#if TARGET_HOST_MS_WINDOWS
+# define HAVE_VPRINTF 1
+#endif
+
+#if !defined(HAVE_VPRINTF) && !defined(HAVE_DOPRNT)
+/* XXX warning directive here? */
+# define HAVE_VPRINTF 1
+#endif
+
+/* MinGW may lack a prototype for ChangeDisplaySettingsEx() (depending on the version?) */
+#if TARGET_HOST_MS_WINDOWS && !defined(ChangeDisplaySettingsEx)
+LONG WINAPI ChangeDisplaySettingsExA(LPCSTR,LPDEVMODEA,HWND,DWORD,LPVOID);
+LONG WINAPI ChangeDisplaySettingsExW(LPCWSTR,LPDEVMODEW,HWND,DWORD,LPVOID);
+# ifdef UNICODE
+# define ChangeDisplaySettingsEx ChangeDisplaySettingsExW
+# else
+# define ChangeDisplaySettingsEx ChangeDisplaySettingsExA
+# endif
+#endif
+
+#if defined(_MSC_VER) || defined(__WATCOMC__)
+/* strdup() is non-standard, for all but POSIX-2001 */
+#define strdup _strdup
+#endif
+
+/* M_PI is non-standard (defined by BSD, not ISO-C) */