diff --git a/CHANGES b/CHANGES
index da18aa463..1fd0a204d 100644
--- a/CHANGES
+++ b/CHANGES
@@ -3,6 +3,8 @@ CHANGES IN FLTK 1.1.8
 	- Documentation fixes (STR #1454, STR #1455, STR #1456,
 	  STR #1457, STR #1458, STR #1460, STR #1481, STR #1578,
 	  STR #1639, STR #1645, STR #1644)
+	- Made -O3 the default optimization on Cygwin/Mingw since
+	  -Os currently creates bad code (STR #1656)
 	- OSF/Tru64 now uses 'install-sh' instead of 'install' to
 	  accomodate for a missing '-d' option (STR #1632)
 	- New option in Fluid project settings to translate all
diff --git a/configure.in b/configure.in
index f494e1593..71388a34d 100644
--- a/configure.in
+++ b/configure.in
@@ -615,7 +615,10 @@ case $uname in
 	LDFLAGS="-mwindows $LDFLAGS"
 	DSOFLAGS="-mwindows $DSOFLAGS"
 	LIBS="$LIBS -lole32 -luuid -lcomctl32 -lwsock32"
-	OPTIM="$OPTIM"
+	if test "x$with_optim" = x; then
+	    dnl Avoid -Os optimization on Cygwin/Mingw
+	    with_optim="-O3"
+	fi
 
 	if test x$enable_gl != xno; then
 	    AC_CHECK_HEADER(GL/gl.h,