diff --git a/src/calibre/utils/imageops/imageops.cpp b/src/calibre/utils/imageops/imageops.cpp
index 52f68f1ff4..71df9666e5 100644
--- a/src/calibre/utils/imageops/imageops.cpp
+++ b/src/calibre/utils/imageops/imageops.cpp
@@ -5,8 +5,8 @@
  * Distributed under terms of the GPL3 license.
  */
 
-#include <stdexcept>
 #include "imageops.h"
+#include <stdexcept>
 #include <QVector>
 #include <cmath>
 
diff --git a/src/calibre/utils/imageops/imageops.h b/src/calibre/utils/imageops/imageops.h
index 1b5a0ed56d..e477eb8105 100644
--- a/src/calibre/utils/imageops/imageops.h
+++ b/src/calibre/utils/imageops/imageops.h
@@ -7,8 +7,8 @@
 
 #pragma once
 
-#include <QImage>
 #include <Python.h>
+#include <QImage>
 
 QImage remove_borders(const QImage &image, double fuzz);
 QImage grayscale(const QImage &image);
diff --git a/src/calibre/utils/imageops/imageops.sip b/src/calibre/utils/imageops/imageops.sip
index ed72af2b3c..d1ff602fee 100644
--- a/src/calibre/utils/imageops/imageops.sip
+++ b/src/calibre/utils/imageops/imageops.sip
@@ -7,6 +7,7 @@
 %Import QtGui/QtGuimod.sip
 %ModuleCode
 #include <imageops.h>
+#include <stdexcept>
 #define IMAGEOPS_PREFIX \
             if (a0->isNull()) { PyErr_SetString(PyExc_ValueError, "Cannot operate on null QImage"); return NULL; } \
             try {
diff --git a/src/calibre/utils/imageops/quantize.cpp b/src/calibre/utils/imageops/quantize.cpp
index c42ee0d8d4..dfc7c20a92 100644
--- a/src/calibre/utils/imageops/quantize.cpp
+++ b/src/calibre/utils/imageops/quantize.cpp
@@ -12,12 +12,12 @@
  * Distributed under terms of the GPL3 license.
  */
 
-#include <algorithm>
+#include "imageops.h"
+#include <stdexcept>
 #include <cmath>
 #include <stdio.h>
 #include <QVector>
 #include <QStringList>
-#include "imageops.h"
 
 // Increasing this number improves quality but also increases running time and memory consumption
 static const size_t MAX_LEAVES = 2000;
@@ -31,6 +31,9 @@ static inline double log2(double x) { return log(x) / log((double)2) ; }
 #endif
 #else
 #include <stdint.h>
+#ifndef UINT64_MAX
+#define UINT64_MAX 18446744073709551615ULL
+#endif
 #endif
 #define MAX_DEPTH 8
 #define MAX_COLORS 256