Add -Wno-strict-prototypes to suppress new warnings.

Bug: http://b/155835175
Test: m with aosp_blueline
Change-Id: I9625fa0ae8b463cf604bd392d2c6e39559997be9
diff --git a/Android.bp b/Android.bp
index 11a2ab6..f4e6144 100644
--- a/Android.bp
+++ b/Android.bp
@@ -32,6 +32,7 @@
         "-Wno-register",
         "-Wno-shift-count-overflow",
         "-Wno-sign-compare",
+        "-Wno-strict-prototypes",
         "-Wno-tautological-compare",
         "-Wno-tautological-constant-out-of-range-compare",
         "-Wno-unused-parameter",