https://bugs.gentoo.org/508708

From 1d2540d8f66d344d3adcfa0db626690d43187dbb Mon Sep 17 00:00:00 2001
From: Mike Frysinger <vapier@gentoo.org>
Date: Fri, 25 Apr 2014 13:39:21 -0400
Subject: [PATCH 4/4] upgrade files atomically

---
 opengl.eselect | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/opengl.eselect b/opengl.eselect
index 1b72c18..0e1e52a 100644
--- a/opengl.eselect
+++ b/opengl.eselect
@@ -71,13 +71,13 @@ upgrade_file() {
 	[[ -f ${file} ]] || return
 	filename=$(basename "${file}")
 
-	if [[ -f ${filename} || ( -L ${filename} && ! -e ${filename} ) ]] ; then
-		rm -f "${filename}" || die -q "Failed to delete ${workdir}/${filename}"
-	fi
-
-	#echo "DEBUG: ln -s \"${linkfile}\" \"${filename}\""
+	#echo "DEBUG: ln -sf \"${linkfile}\" \"${filename}\""
 	if [[ "x${REMOVE_ONLY}" == "xfalse" ]]; then
-		ln -s "${linkfile}" "${filename}" || die -q "Failed to create symlink ${workdir}/${filename}"
+		# Upgrade the file atomically. #508708
+		ln -sf "${linkfile}" "${filename}~" || die -q "Failed to create symlink ${workdir}/${filename}~"
+		mv -f "${filename}~" "${filename}" || die -q "Failed to update ${workdir}/${filename}"
+	elif [[ -f ${filename} || ( -L ${filename} && ! -e ${filename} ) ]] ; then
+		rm -f "${filename}" || die -q "Failed to delete ${workdir}/${filename}"
 	fi
 }
 
-- 
1.9.2