Instrumented libraries: fix libasound2 build on Trusty.

BUG=414189
TBR=glider@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/716883002

Cr-Original-Commit-Position: refs/heads/master@{#303682}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: baa4589daf1c7fce3698f5bee819b8268aae0fb3
diff --git a/scripts/libasound2.sh b/scripts/libasound2.sh
index 765914b..d7c59a4 100755
--- a/scripts/libasound2.sh
+++ b/scripts/libasound2.sh
@@ -11,3 +11,6 @@
 autoheader
 autoconf
 automake --foreign --copy --add-missing
+
+# Do not warn about undefined sanitizer symbols in object files.
+sed -i "s/\(-Wl,--no-undefined\|-Wl,-z,defs\)//g" ./configure