tflite: Add libm in linker options

BUG=b:305999697
TEST=Add async_delegate_test into ebuild then emerge tensorflow

Change-Id: Iab6ed2d49a583211f41f5541887273952b90ebff
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/tflite/+/5380175
Commit-Queue: Tommy Chiang <ototot@google.com>
Reviewed-by: Tommy Chiang <ototot@google.com>
Auto-Submit: Shik Chen <shik@chromium.org>
Tested-by: Shik Chen <shik@chromium.org>

.bazelrc

diff --git a/.bazelrc b/.bazelrc
index 105ac16..b88791a 100644
--- a/.bazelrc
+++ b/.bazelrc
@@ -24,6 +24,12 @@
 build --define=no_aws_support=true
 build --define=no_hdfs_support=true
 
+# Ensure that libm is linked to avoid undefined symbols error. This is also set
+# in the upstream Tensorflow repo in some configurations. See
+# https://github.com/bazelbuild/bazel/issues/12023 for more details.
+build --linkopt="-lm"
+build --host_linkopt="-lm"
+
 # Use --config=host_clang to build things with clang on host.
 build:host_clang --repo_env=CC=clang