Fix some wrong behavior with sysroot option.

Fix reading the outdated caches.
Apply a patch to make it MT-safe more.

fontconfig-fix-test.patch

@@ -10,3 +10,32 @@ diff -pruN fontconfig-2.13.92.orig/test/run-test.sh fontconfig-2.13.92/test/run-
      dotest "MT-safe global config"
      prep
      curl -s -o $FONTDIR/noto.zip https://noto-website-2.storage.googleapis.com/pkgs/NotoSans-hinted.zip
+From 8bddcb113779178e5b5ed711db08d9bfbff924cc Mon Sep 17 00:00:00 2001
+From: Akira TAGOH <akira@tagoh.org>
+Date: Thu, 5 Dec 2019 19:55:06 +0900
+Subject: [PATCH] Fix a test fail when no bwrap was available
+
+Fixes https://gitlab.freedesktop.org/fontconfig/fontconfig/issues/201
+---
+ test/run-test.sh | 5 ++---
+ 1 file changed, 2 insertions(+), 3 deletions(-)
+
+diff --git a/test/run-test.sh b/test/run-test.sh
+index e1ee6d0..9b2e54b 100644
+--- a/test/run-test.sh
++++ b/test/run-test.sh
+@@ -40,9 +40,8 @@ ECHO=true
+ FCLIST="$LOG_COMPILER ../fc-list/fc-list$EXEEXT"
+ FCCACHE="$LOG_COMPILER ../fc-cache/fc-cache$EXEEXT"
+ 
+-which bwrap > /dev/null 2>&1
+-if [ $? -eq 0 ]; then
+-    BWRAP=`which bwrap`
++if [ -x "$(command -v bwrap)" ]; then
++    BWRAP="$(command -v bwrap)"
+ fi
+ 
+ FONT1=$TESTDIR/4x6.pcf
+-- 
+2.24.1
+