diff --git a/configure b/configure
index 3f63cd86..ef72e024 100755
--- a/configure
+++ b/configure
@@ -837,6 +837,7 @@ with_jpeg12_include_dir
 with_jpeg12_lib
 enable_cxx
 with_x
+enable_win32_io
 enable_strip_chopping
 with_default_strip_size
 enable_defer_strile_load
@@ -1521,6 +1522,8 @@ Optional Features:
   --enable-jpeg12         enable libjpeg 8/12bit dual mode
   --enable-cxx            enable C++ stream API building (requires C++
                           compiler)
+  --disable-win32-io      disable Win32 I/O (Windows only, enabled by default
+                          except for Cygwin)
   --disable-strip-chopping
                           disable support for strip chopping (whether or not
                           to convert single-strip uncompressed images to
@@ -20346,19 +20349,32 @@ fi
 
 
 
+# Check whether --enable-win32-io was given.
+if test "${enable_win32_io+set}" = set; then :
+  enableval=$enable_win32_io;
+fi
+
+
 win32_io_ok=no
 case "${host_os}" in
     cygwin*)
+        if test x"$ac_cv_header_windows_h" = xyes -a "x$enable_win32_io" = xyes ; then
+            win32_io_ok=yes
+	fi
         ;;
     *)
-        if test x"$ac_cv_header_windows_h" = xyes; then
+        if test x"$ac_cv_header_windows_h" = xyes -a ! "x$enable_win32_io" = xno ; then
             win32_io_ok=yes
-
-$as_echo "#define USE_WIN32_FILEIO 1" >>confdefs.h
-
 	fi
         ;;
 esac
+
+if test "$win32_io_ok" = "yes" ; then
+
+$as_echo "#define USE_WIN32_FILEIO 1" >>confdefs.h
+
+fi
+
  if test "$win32_io_ok" = yes; then
   WIN32_IO_TRUE=
   WIN32_IO_FALSE='#'
diff --git a/libtiff/tif_getimage.c b/libtiff/tif_getimage.c
index 1095c25e..f49b73fd 100644
--- a/libtiff/tif_getimage.c
+++ b/libtiff/tif_getimage.c
@@ -1,4 +1,4 @@
-/* $Id: tif_getimage.c,v 1.89 2015-06-15 16:13:46 faxguy Exp $ */
+/* $Id: tif_getimage.c,v 1.90 2015-06-17 01:34:08 bfriesen Exp $ */
 
 /*
  * Copyright (c) 1991-1997 Sam Leffler
@@ -660,7 +660,7 @@ gtTileContig(TIFFRGBAImage* img, uint32* raster, uint32 w, uint32 h)
                 break;
             }
             pos = ((row+img->row_offset) % th) * TIFFTileRowSize(tif) + \
-		   ((int32) fromskew * img->samplesperpixel);
+		   ((tmsize_t) fromskew * img->samplesperpixel);
 	    if (tocol + this_tw > w) 
 	    {
 		/*
@@ -827,7 +827,7 @@ gtTileSeparate(TIFFRGBAImage* img, uint32* raster, uint32 w, uint32 h)
 			}
 
 			pos = ((row+img->row_offset) % th) * TIFFTileRowSize(tif) + \
-			   ((int32) fromskew * img->samplesperpixel);
+			   ((tmsize_t) fromskew * img->samplesperpixel);
 			if (tocol + this_tw > w) 
 			{
 				/*
@@ -937,7 +937,7 @@ gtStripContig(TIFFRGBAImage* img, uint32* raster, uint32 w, uint32 h)
 		}
 
 		pos = ((row + img->row_offset) % rowsperstrip) * scanline + \
-			((int32) img->col_offset * img->samplesperpixel);
+			((tmsize_t) img->col_offset * img->samplesperpixel);
 		(*put)(img, raster+y*w, 0, y, w, nrow, fromskew, toskew, buf + pos);
 		y += (flip & FLIP_VERTICALLY ? -(int32) nrow : (int32) nrow);
 	}
@@ -1069,7 +1069,7 @@ gtStripSeparate(TIFFRGBAImage* img, uint32* raster, uint32 w, uint32 h)
 		}
 
 		pos = ((row + img->row_offset) % rowsperstrip) * scanline + \
-			((int32) img->col_offset * img->samplesperpixel);
+			((tmsize_t) img->col_offset * img->samplesperpixel);
 		(*put)(img, raster+y*w, 0, y, w, nrow, fromskew, toskew, p0 + pos, p1 + pos,
 		    p2 + pos, (alpha?(pa+pos):NULL));
 		y += (flip & FLIP_VERTICALLY ? -(int32) nrow : (int32) nrow);