diff --git a/magick/threshold.c b/magick/threshold.c
index 1a57b05..2c07fb1 100644
--- a/magick/threshold.c
+++ b/magick/threshold.c
@@ -200,19 +200,19 @@
       sync;
 
     register const IndexPacket
-      *__restrict indexes;
+      *restrict indexes;
 
     register const PixelPacket
-      *__restrict p;
+      *restrict p;
 
     register IndexPacket
-      *__restrict threshold_indexes;
+      *restrict threshold_indexes;
 
     register long
       x;
 
     register PixelPacket
-      *__restrict q;
+      *restrict q;
 
     if (status == MagickFalse)
       continue;
@@ -391,13 +391,13 @@
   for (y=0; y < (long) image->rows; y++)
   {
     register IndexPacket
-      *__restrict indexes;
+      *restrict indexes;
 
     register long
       x;
 
     register PixelPacket
-      *__restrict q;
+      *restrict q;
 
     if (status == MagickFalse)
       continue;
@@ -577,13 +577,13 @@
   for (y=0; y < (long) image->rows; y++)
   {
     register IndexPacket
-      *__restrict indexes;
+      *restrict indexes;
 
     register long
       x;
 
     register PixelPacket
-      *__restrict q;
+      *restrict q;
 
     if (status == MagickFalse)
       continue;
@@ -726,7 +726,7 @@
         i;
 
       register PixelPacket
-        *__restrict q;
+        *restrict q;
 
       q=image->colormap;
       for (i=0; i < (long) image->colors; i++)
@@ -752,13 +752,13 @@
   for (y=0; y < (long) image->rows; y++)
   {
     register IndexPacket
-      *__restrict indexes;
+      *restrict indexes;
 
     register long
       x;
 
     register PixelPacket
-      *__restrict q;
+      *restrict q;
 
     if (status == MagickFalse)
       continue;
@@ -1482,13 +1482,13 @@
     for (y=0; y < (long) image->rows; y++)
     {
       register IndexPacket
-        *__restrict indexes;
+        *restrict indexes;
 
       register long
         x;
 
       register PixelPacket
-        *__restrict q;
+        *restrict q;
 
       if (status == MagickFalse)
         continue;
@@ -1704,14 +1704,14 @@
           sync;
 
         register IndexPacket
-          *__restrict indexes;
+          *restrict indexes;
 
         register long
           id,
           x;
 
         register PixelPacket
-          *__restrict q;
+          *restrict q;
 
         if (status == MagickFalse)
           continue;
@@ -1778,14 +1778,14 @@
   for (y=0; y < (long) image->rows; y++)
   {
     register IndexPacket
-      *__restrict indexes;
+      *restrict indexes;
 
     register long
       id,
       x;
 
     register PixelPacket
-      *__restrict q;
+      *restrict q;
 
     if (status == MagickFalse)
       continue;
@@ -2005,13 +2005,13 @@
   for (y=0; y < (long) image->rows; y++)
   {
     register IndexPacket
-      *__restrict indexes;
+      *restrict indexes;
 
     register long
       x;
 
     register PixelPacket
-      *__restrict q;
+      *restrict q;
 
     if (status == MagickFalse)
       continue;