diff --git a/CHANGES b/CHANGES
index 2310d895b..bd5c2beba 100644
--- a/CHANGES
+++ b/CHANGES
@@ -3,6 +3,8 @@ CHANGES IN FLTK 1.3.5					RELEASED: ??? ?? 2017
 
 Bug fixes and other improvements
 
+	- Fix a MinGW build error with new MinGW versions as of Feb 2018
+	  (undefined S_OK and __FD_ISSET), see STR #3454.
 	- Windows/CMake: Add missing definition of WIN32 for Windows builds.
 	  This seems to be necessary for VS2017 and other compilers that
 	  don't #define WIN32, but FLTK relies on this preprocessor macro.
diff --git a/src/Fl.cxx b/src/Fl.cxx
index 597524b86..f580159f3 100644
--- a/src/Fl.cxx
+++ b/src/Fl.cxx
@@ -3,7 +3,7 @@
 //
 // Main event handling code for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 1998-2015 by Bill Spitzak and others.
+// Copyright 1998-2018 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -39,8 +39,24 @@
 # endif
 #endif
 
+
+// STR #3454: We must #define FD_ISSET before we #include winsock2.h
+// to fix an undefined reference (__FD_ISSET). (AlbrechtS Feb 2018)
+// Other portions of the fix for STR #3454 are in src/Fl_win32.cxx.
+// This fix is only necessary for MinGW.
+
+#ifdef __MINGW32__
+static void * get_wsock_mod();
+typedef int(__stdcall *fl_wsk_fd_is_set_f)(unsigned int, void *);
+static fl_wsk_fd_is_set_f fl_wsk_fd_is_set = 0;
+
+#define FD_ISSET(S,SET) \
+  (get_wsock_mod() ? fl_wsk_fd_is_set(S, SET) : 0)
+#endif // __MINGW32__
+
 // recent versions of MinGW warn: "Please include winsock2.h before windows.h",
 // hence we must include winsock2.h before FL/Fl.H (A.S. Dec. 2010, IMM May 2011)
+
 #if defined(WIN32) && !defined(__CYGWIN__)
 #  include <winsock2.h>
 #endif
diff --git a/src/Fl_win32.cxx b/src/Fl_win32.cxx
index 2c49ea010..2c0f2339b 100644
--- a/src/Fl_win32.cxx
+++ b/src/Fl_win32.cxx
@@ -3,7 +3,7 @@
 //
 // WIN32-specific code for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 1998-2016 by Bill Spitzak and others.
+// Copyright 1998-2018 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -60,6 +60,11 @@
 #include <ole2.h>
 #include <shellapi.h>
 
+// New versions of MinGW (as of Feb 2018) need to include winerror.h to
+// #define S_OK which used to be defined in ole2.h (STR #3454)
+
+#include <winerror.h>
+
 //
 // USE_ASYNC_SELECT - define it if you have WSAAsyncSelect()...
 // USE_ASYNC_SELECT is OBSOLETED in 1.3 for the following reasons:
@@ -100,14 +105,24 @@ static bool initial_clipboard = true;
 // note: winsock2.h has been #include'd in Fl.cxx
 #define WSCK_DLL_NAME "WS2_32.DLL"
 
+// Patch for MinGW (__MINGW32__): see STR #3454 and src/Fl.cxx
+#ifdef __MINGW32__
+typedef int(WINAPI *fl_wsk_fd_is_set_f)(unsigned int, void *);
+#else
+typedef int(WINAPI *fl_wsk_fd_is_set_f)(SOCKET, fd_set *);
+static fl_wsk_fd_is_set_f fl_wsk_fd_is_set = 0;
+#endif
+
 typedef int (WINAPI* fl_wsk_select_f)(int, fd_set*, fd_set*, fd_set*, const struct timeval*);
-typedef int (WINAPI* fl_wsk_fd_is_set_f)(SOCKET, fd_set *);
 
 static HMODULE s_wsock_mod = 0;
 static fl_wsk_select_f s_wsock_select = 0;
-static fl_wsk_fd_is_set_f fl_wsk_fd_is_set = 0;
 
+#ifdef __MINGW32__
+static void * get_wsock_mod() {
+#else
 static HMODULE get_wsock_mod() {
+#endif
   if (!s_wsock_mod) {
     s_wsock_mod = LoadLibrary(WSCK_DLL_NAME);
     if (s_wsock_mod==NULL)