Make libstatslog static-linkage compatible.

libstatslog is a blocker for some fuzzing. Our continuous fuzzing
infrastructure requires a statically-linked binary, and things depend on
libstatslog down the chain. We should allow libstatslog to be linked
statically.

Bug: N/A
Test: m libstatslog
Change-Id: Ic742a90daf6cbb5d197784416626256bfb6182b7