https://bugs.gentoo.org/870217
https://forum.xpdfreader.com/viewtopic.php?t=42367
https://github.com/rrthomas/libpaper/issues/29
--- a/xpdf/GlobalParams.cc
+++ b/xpdf/GlobalParams.cc
@@ -655,7 +655,7 @@ GlobalParams::GlobalParams(const char *cfgFileName) {
   base14SysFonts = new GHash(gTrue);
   sysFonts = new SysFontList();
 #if HAVE_PAPER_H
-  char *paperName;
+  const char *paperName;
   const struct paper *paperType;
   paperinit();
   if ((paperName = systempapername())) {