diff --git a/src/third_party/libjpeg-turbo/cmyk.h b/src/third_party/libjpeg-turbo/cmyk.h
new file mode 100644
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+++ b/src/third_party/libjpeg-turbo/cmyk.h
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+/*
+ * cmyk.h
+ *
+ * Copyright (C) 2017-2018, D. R. Commander.
+ * For conditions of distribution and use, see the accompanying README.ijg
+ * file.
+ *
+ * This file contains convenience functions for performing quick & dirty
+ * CMYK<->RGB conversion.  This algorithm is suitable for testing purposes
+ * only.  Properly converting between CMYK and RGB requires a color management
+ * system.
+ */
+
+#ifndef CMYK_H
+#define CMYK_H
+
+#include <jinclude.h>
+#define JPEG_INTERNALS
+#include <jpeglib.h>
+#include "jconfigint.h"
+
+
+/* Fully reversible */
+
+INLINE
+LOCAL(void)
+rgb_to_cmyk(JSAMPLE r, JSAMPLE g, JSAMPLE b, JSAMPLE *c, JSAMPLE *m,
+            JSAMPLE *y, JSAMPLE *k)
+{
+  double ctmp = 1.0 - ((double)r / 255.0);
+  double mtmp = 1.0 - ((double)g / 255.0);
+  double ytmp = 1.0 - ((double)b / 255.0);
+  double ktmp = MIN(MIN(ctmp, mtmp), ytmp);
+
+  if (ktmp == 1.0) ctmp = mtmp = ytmp = 0.0;
+  else {
+    ctmp = (ctmp - ktmp) / (1.0 - ktmp);
+    mtmp = (mtmp - ktmp) / (1.0 - ktmp);
+    ytmp = (ytmp - ktmp) / (1.0 - ktmp);
+  }
+  *c = (JSAMPLE)(255.0 - ctmp * 255.0 + 0.5);
+  *m = (JSAMPLE)(255.0 - mtmp * 255.0 + 0.5);
+  *y = (JSAMPLE)(255.0 - ytmp * 255.0 + 0.5);
+  *k = (JSAMPLE)(255.0 - ktmp * 255.0 + 0.5);
+}
+
+
+/* Fully reversible only for C/M/Y/K values generated with rgb_to_cmyk() */
+
+INLINE
+LOCAL(void)
+cmyk_to_rgb(JSAMPLE c, JSAMPLE m, JSAMPLE y, JSAMPLE k, JSAMPLE *r, JSAMPLE *g,
+            JSAMPLE *b)
+{
+  *r = (JSAMPLE)((double)c * (double)k / 255.0 + 0.5);
+  *g = (JSAMPLE)((double)m * (double)k / 255.0 + 0.5);
+  *b = (JSAMPLE)((double)y * (double)k / 255.0 + 0.5);
+}
+
+
+#endif /* CMYK_H */