Add -fno-exceptions to default build config

* C++ exceptions are expensive and are not used in our code
* We need to disable exception to achieve desired behavior for
  std::stoi, which we don't want it to crash when failing to parse an
  incoming integer

Test: make, net_test_osi
Change-Id: Idc363ff1f25f085c75df3c473ee4d2a210af3b17

system/build/Android.bp

@@ -18,7 +18,8 @@ fluoride_defaults {
     name: "fluoride_types_defaults",
     cflags: [
         "-DEXPORT_SYMBOL=__attribute__((visibility(\"default\")))",
-        "-fvisibility=hidden",
+        "-fno-exceptions",
+	"-fvisibility=hidden",
         "-Wall",
         "-Wextra",
         "-Werror",