Backport the lld patch in sandbox to Chrome OS sandbox version.
Patch is slightly modified from upstream to apply to Chrome OS.

https://gitweb.gentoo.org/proj/sandbox.git/patch/?id=3c001036637930152c038d084334d9a7311ffc6e

From: Sergei Trofimovich <slyfox@gentoo.org>
Date: Thu, 7 Mar 2019 23:41:54 +0000
Subject: configure.ac: add lld detection support

With this change
    $ ./configure CC=clang LDFLAGS='-Wl,--hash-style=gnu -fuse-ld=lld'
    $ make check
exposes 35 test failures

Bug: https://bugs.gentoo.org/672918
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
---
 configure.ac | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index 8c1866c..3f242b4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -352,9 +352,17 @@ try_link() {
 	) 1>&AS_MESSAGE_LOG_FD
 }
 LIBC_PATH=$(AS_IF(
-	dnl GNU linker (bfd & gold)
+	dnl GNU linker (bfd & gold) searching for
+	dnl (bfd)  "attempt to open /usr/lib/gcc/x86_64-pc-linux-gnu/8.3.0/../../../../lib64/libc.so succeeded"
+	dnl (gold) "/usr/lib/gcc/x86_64-pc-linux-gnu/8.3.0/../../../../x86_64-pc-linux-gnu/bin/ld: Attempt to open /lib64/libc.so.6 succeeded"
+	dnl if log does not contain "attempt" word then it's not a GNU linker
+	[try_link -Wl,--verbose && grep -q '[[Aa]]ttempt' libctest.log],
+		[$AWK '/[[Aa]]ttempt to open/ { if (($(NF-1) ~ /\/libc\.so/) && ($NF == "succeeded")) LIBC = $(NF-1); }; END {print LIBC}' libctest.log],
+	dnl LLVM lld searching for latest (successful) entry of
+	dnl     "ld.lld: /usr/lib/gcc/x86_64-pc-linux-gnu/8.3.0/../../../../lib64/libc.so"
+	dnl     "ld.lld: /lib64/libc.so.6"
 	[try_link -Wl,--verbose],
-		[$AWK '/ttempt to open/ { if (($(NF-1) ~ /\/libc\.so/) && ($NF == "succeeded")) LIBC = $(NF-1); }; END {print LIBC}' libctest.log],
+		[$EGREP -o '/[[^ ]]*/libc.so.*' libctest.log | tail -n1],
 	dnl Solaris linker
 	[try_link -Wl,-m],
 		[set -- `$EGREP -o '/[[^ ]]*/libc.so' libctest.log`; echo $1]