Implement a workaround for thread_local on aarch64

Some versions of lld break thread_local on aarch64. There's a
minimally-painful workaround for it, so let's apply that.

Change-Id: I706de9e280cc15006e5767ee10d961cb2d99352c
diff --git a/aos/libc/BUILD b/aos/libc/BUILD
index 234c29a..35b6629 100644
--- a/aos/libc/BUILD
+++ b/aos/libc/BUILD
@@ -9,6 +9,7 @@
         "aos_strsignal.h",
     ],
     deps = [
+        "//aos:thread_local",
         "@com_github_google_glog//:glog",
     ],
 )
@@ -53,6 +54,9 @@
     hdrs = [
         "aos_strerror.h",
     ],
+    deps = [
+        "//aos:thread_local",
+    ],
 )
 
 cc_test(