Fix CVE-2017-14166:

https://github.com/libarchive/libarchive/issues/935
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-14166

Patch copied from upstream source repository:

https://github.com/libarchive/libarchive/commit/fa7438a0ff4033e4741c807394a9af6207940d71

From fa7438a0ff4033e4741c807394a9af6207940d71 Mon Sep 17 00:00:00 2001
From: Joerg Sonnenberger <joerg@bec.de>
Date: Tue, 5 Sep 2017 18:12:19 +0200
Subject: [PATCH] Do something sensible for empty strings to make fuzzers
 happy.

---
 libarchive/archive_read_support_format_xar.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/libarchive/archive_read_support_format_xar.c b/libarchive/archive_read_support_format_xar.c
index 7a22beb9d..93eeacc5e 100644
--- a/libarchive/archive_read_support_format_xar.c
+++ b/libarchive/archive_read_support_format_xar.c
@@ -1040,6 +1040,9 @@ atol10(const char *p, size_t char_cnt)
 	uint64_t l;
 	int digit;
 
+	if (char_cnt == 0)
+		return (0);
+
 	l = 0;
 	digit = *p - '0';
 	while (digit >= 0 && digit < 10  && char_cnt-- > 0) {
@@ -1054,7 +1057,10 @@ atol8(const char *p, size_t char_cnt)
 {
 	int64_t l;
 	int digit;
-        
+
+	if (char_cnt == 0)
+		return (0);
+
 	l = 0;
 	while (char_cnt-- > 0) {
 		if (*p >= '0' && *p <= '7')
43dfd1bb8d2a7d9e049a8580'>tree</a><a href='/guix/commit/build-aux/test-env.in?id=5aaef5c5decbf4dd43dfd1bb8d2a7d9e049a8580'>commit</a><a href='/guix/diff/build-aux/test-env.in?id=5aaef5c5decbf4dd43dfd1bb8d2a7d9e049a8580'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/build-aux/test-env.in'>
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<div class='path'>path: <a href='/guix/log/?id=5aaef5c5decbf4dd43dfd1bb8d2a7d9e049a8580'>root</a>/<a href='/guix/log/build-aux?id=5aaef5c5decbf4dd43dfd1bb8d2a7d9e049a8580'>build-aux</a>/<a href='/guix/log/build-aux/test-env.in?id=5aaef5c5decbf4dd43dfd1bb8d2a7d9e049a8580'>test-env.in</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/build-aux/test-env.in?id=5aaef5c5decbf4dd43dfd1bb8d2a7d9e049a8580&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2018-05-13 23:16:16 +0200'>2018-05-13</span></td><td><a href='/guix/commit/build-aux/test-env.in?id=9e7b87ddc51c640c529d445e350c3d6ef43e301d'>build: 'test-env' does not 'guix download' non-existent files.</a><span class='msg-avail'>...<span class='msg-tooltip'>Reported by uniq10.

* build-aux/test-env.in: Check whether FILE exists before invoking 'guix
download'.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-04-22 23:50:49 +0200'>2018-04-22</span></td><td><a href='/guix/commit/build-aux/test-env.in?id=479c0e3f60f54e3c3a02f71efeb49119e20d2a96'>build: Fix possible race condition in 'test-env'.</a><span class='msg-avail'>...<span class='msg-tooltip'>Reported by Mark H Weaver &lt;mhw@netris.org&gt;.

* build-aux/test-env.in: Add 'guile' invocation before 'guix download'
invocation to make sure 'guix-daemon' is listening.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2017-08-28 23:51:16 +0200'>2017-08-28</span></td><td><a href='/guix/commit/build-aux/test-env.in?id=4f024ef3181c5235ff11789e8c8f62722f974787'>build: Remove code to download the Guile bootstrap tarball.</a><span class='msg-avail'>...<span class='msg-tooltip'>* build-aux/download.scm: Remove.
* Makefile.am (EXTRA_DIST): Remove it.
(check-system): Remove dependency on $(BOOTSTRAP_GUILE_TARBALLS).
* gnu/local.mk (nodist_bootstrap_x86_64_linux_DATA)
(nodist_bootstrap_i686_linux_DATA, nodist_bootstrap_armhf_linux_DATA)
(nodist_bootstrap_aarch64_linux_DATA, nodist_bootstrap_mips64el_linux_DATA)
(BOOTSTRAP_GUILE_TARBALLS, DISTCLEANFILES, DOWNLOAD_FILE)
(%D%/packages/bootstrap/x86_64-linux/guile-2.0.9.tar.xz)
(%D%/packages/bootstrap/i686-linux/guile-2.0.9.tar.xz)
(%D%/packages/bootstrap/armhf-linux/guile-2.0.11.tar.xz)
(%D%/packages/bootstrap/aarch64-linux/guile-2.0.14.tar.xz)
(%D%/packages/bootstrap/mips64el-linux/guile-2.0.9.tar.xz): Remove.
* build-aux/test-env.in: Add "guix download" invocation when
gnu/packages/bootstrap/guile* exists.
</span></span></td><td>Ludovic Courtès</td></tr>