Revert "Revert "Use AAPT2 by default""

This reverts commit 777cf2c450bfa5ff2af4214647d54b095a8f19c4.

Reason for revert: manifest merger is used for libraries forced to aapt2 now

Bug: 79481102
Test: m checkbuild
Change-Id: I9b67fd2a9b3234798b2aac879b5242c2097b3863
diff --git a/core/force_aapt2.mk b/core/force_aapt2.mk
index a097bd2..ede6fd4 100644
--- a/core/force_aapt2.mk
+++ b/core/force_aapt2.mk
@@ -17,7 +17,7 @@
 # Including this makefile will force AAPT2 on if FORCE_AAPT2==true,
 # rewriting some properties to convert standard AAPT usage to AAPT2.
 
-ifeq ($(FORCE_AAPT2),true)
+ifneq ($(FORCE_AAPT2),false)
   ifeq ($(LOCAL_USE_AAPT2),)
     # Force AAPT2 on
     LOCAL_USE_AAPT2 := true
@@ -47,7 +47,6 @@
     ifeq (,$(strip $(LOCAL_MANIFEST_FILE)$(LOCAL_FULL_MANIFEST_FILE)))
       ifeq (,$(wildcard $(LOCAL_PATH)/AndroidManifest.xml))
         # work around missing manifests by creating a default one
-        $(call pretty-warning, Missing manifest file)
         LOCAL_FULL_MANIFEST_FILE := $(call local-intermediates-dir,COMMON)/DefaultManifest.xml
         ifdef LOCAL_MIN_SDK_VERSION
           my_manifest_min_sdk_version := $(LOCAL_MIN_SDK_VERSION)