Turn on -Wall for recovery modules

Turn on -Wall for all modules. Also remove the obsolete file_cmp() in
apply_patch test and now() in wear_ui.

The only exception is lib_edify due to the unused functions in the
intermediate cpp files generated from the lex files. It will be handled
in a seperate CL.

Bug: 64939312
Test: mma, unit tests pass
Change-Id: Ic53f76b60b6401ab20db3d98130d674c08e3702f
diff --git a/updater/Android.mk b/updater/Android.mk
index 86dc48e..1218160 100644
--- a/updater/Android.mk
+++ b/updater/Android.mk
@@ -66,6 +66,7 @@
     external/e2fsprogs/misc
 
 LOCAL_CFLAGS := \
+    -Wall \
     -Wno-unused-parameter \
     -Werror
 
@@ -91,6 +92,7 @@
     $(LOCAL_PATH)/include
 
 LOCAL_CFLAGS := \
+    -Wall \
     -Wno-unused-parameter \
     -Werror