From 0cf721244a819cbd67b2bc0a8c8a97adcb53944e Mon Sep 17 00:00:00 2001
From: Andrew Dunstan <andrew@dunslane.net>
Date: Thu, 26 Oct 2017 10:10:37 -0400
Subject: [PATCH] Improve gendef.pl diagnostic on failure to open sym file

There have been numerous buildfarm failures but the diagnostic is
currently silent about the reason for failure to open the file. Let's
see if we can get to the bottom of it.

Backpatch to all live branches.
---
 src/tools/msvc/gendef.pl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/tools/msvc/gendef.pl b/src/tools/msvc/gendef.pl
index 8ef0422df9d..247cff0cac3 100644
--- a/src/tools/msvc/gendef.pl
+++ b/src/tools/msvc/gendef.pl
@@ -27,7 +27,7 @@ while (<$ARGV[0]/*.obj>)
 	print ".";
 	system("dumpbin /symbols /out:symbols.out $_ >NUL")
 	  && die "Could not call dumpbin";
-	open(F, "<symbols.out") || die "Could not open symbols.out for $_\n";
+	open(F, "<symbols.out") || die "Could not open symbols.out for $_: $!\n";
 	while (<F>)
 	{
 		s/\(\)//g;