Index: head/converters/pdf2djvu/files/patch-pdf-backend.cc
===================================================================
--- head/converters/pdf2djvu/files/patch-pdf-backend.cc	(revision 524679)
+++ head/converters/pdf2djvu/files/patch-pdf-backend.cc	(revision 524680)
@@ -1,26 +1,66 @@
 --- pdf-backend.cc.orig	2019-06-10 17:06:44 UTC
 +++ pdf-backend.cc
-@@ -103,7 +103,7 @@ static void poppler_error_handler(void *data, ErrorCat
+@@ -48,7 +48,7 @@
+  * ======================
+  */
  
+-static void poppler_error_handler(void *data, ErrorCategory category, pdf::Offset pos, const char *message)
++static void poppler_error_handler_new(ErrorCategory category, pdf::Offset pos, const char *message)
+ {
+   std::string format;
+   const char *category_name = _("PDF error");
+@@ -94,6 +94,11 @@ static void poppler_error_handler(void *data, ErrorCat
+   error_log << std::endl;
+ }
+ 
++static void poppler_error_handler(void *data, ErrorCategory category, pdf::Offset pos, const char *message)
++{
++	  poppler_error_handler_new(category, pos, message);
++}
++
+ #if POPPLER_VERSION < 7000
+ static void poppler_error_handler(void *data, ErrorCategory category, pdf::Offset pos, char *message)
+ {
+@@ -101,10 +106,26 @@ static void poppler_error_handler(void *data, ErrorCat
+ }
+ #endif
+ 
++// for POPPLER_VERSION >= 8500:
++template <typename T1, typename T2> static auto set_error_callback(T1 callback1, T2 callback2) -> decltype(setErrorCallback(callback2))
++{
++	  setErrorCallback(callback2);
++}
++
++// for POPPLER_VERSION < 8500:
++template <typename T1, typename T2> static auto set_error_callback(T1 callback1, T2 callback2) -> decltype(setErrorCallback(callback1, nullptr))
++{
++	  setErrorCallback(callback1, nullptr);
++}
++
  pdf::Environment::Environment()
  {
 -  globalParams = new GlobalParams();
 +  globalParams = std::unique_ptr<GlobalParams>(new GlobalParams);
++#if POPPLER_VERSION >= 7000
++    set_error_callback(poppler_error_handler, poppler_error_handler_new);
++#else
    setErrorCallback(poppler_error_handler, nullptr);
++#endif
  }
  
-@@ -499,12 +499,11 @@ bool pdf::get_glyph(splash::Splash *splash, splash::Fo
+ void pdf::Environment::set_antialias(bool value)
+@@ -499,12 +520,11 @@ bool pdf::get_glyph(splash::Splash *splash, splash::Fo
  void pdf::Renderer::convert_path(pdf::gfx::State *state, splash::Path &splash_path)
  {
    /* Source was copied from <poppler/SplashOutputDev.c>. */
 -  pdf::gfx::Subpath *subpath;
 -  pdf::gfx::Path *path = state->getPath();
 +  auto path = state->getPath();
    int n_subpaths = path->getNumSubpaths();
    for (int i = 0; i < n_subpaths; i++)
    {
 -    subpath = path->getSubpath(i);
 +    auto subpath = path->getSubpath(i);
      if (subpath->getNumPoints() > 0)
      {
        double x1, y1, x2, y2, x3, y3;