diff -pruN old/src/exr.cpp new/src/exr.cpp
--- old/src/exr.cpp	2006-01-04 02:16:52.000000000 +0200
+++ new/src/exr.cpp	2021-05-04 15:28:09.314813642 +0300
@@ -22,10 +22,8 @@
  *
  */
 
-extern "C" {
 #include "histogram-imager.h"
 #include "config.h"
-}
 
 #include <ImfRgbaFile.h>
 using namespace Imf;