From 49d1ca38e41d9fd68176f164722c0e113375737a Mon Sep 17 00:00:00 2001
From: Peter Howkins <flibble@users.sf.net>
Date: Tue, 27 Mar 2018 03:55:32 +0100
Subject: [PATCH] dtdocbook: glibc 2.27 drops support for matherr() support in
 math.h

---
 cde/programs/dtdocbook/tcl/tclMtherr.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/cde/programs/dtdocbook/tcl/tclMtherr.c b/cde/programs/dtdocbook/tcl/tclMtherr.c
index b5a4f5c75..2c02a4308 100644
--- a/cde/programs/dtdocbook/tcl/tclMtherr.c
+++ b/cde/programs/dtdocbook/tcl/tclMtherr.c
@@ -65,6 +65,13 @@ extern int tcl_MathInProgress;
  * that don't really support it.  The compiled procedure is bogus,
  * but it will never be executed on these systems anyway.
  */
+#if defined(linux) && defined(__GLIBC__)
+# include <features.h>
+/* glibc removed matherr() support between 2.26 and 2.27 */
+# if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 27) || __GLIBC__ >= 3
+#  undef NEED_MATHERR
+# endif
+#endif /* linux */
 
 #ifndef NEED_MATHERR
 struct exception {