Use -Werror in frameworks/base

* Fix unused variable and return value warnings.

Bug: 66996870
Test: build with WITH_TIDY=1
Change-Id: I890e65a20848d00559ba5a4f9691be1347b456af
diff --git a/tools/incident_section_gen/Android.bp b/tools/incident_section_gen/Android.bp
index 1756e06..f07445a 100644
--- a/tools/incident_section_gen/Android.bp
+++ b/tools/incident_section_gen/Android.bp
@@ -22,6 +22,8 @@
     cflags: [
         "-g",
         "-O0",
+        "-Wall",
+        "-Werror",
     ],
     srcs: ["main.cpp"],
     shared_libs: [