init: dump stack when aborting

Dump init stacks when aborting either due to LOG(FATAL) or in
userdebug/eng builds due to signals, including signals from
sanitizers.

Doesn't work for static first stage init yet, b/133450393 tracks
that.

Also, ensure that LOG(FATAL) in child processes calls abort() in all
stages of init, not just 2nd stage init.

Bug: 131747478
Test: abort init in various ways and see stacks
Test: hang or crash in backtrace handler and see child reboot
Change-Id: Ib53b5d3e7e814244203f875de016ada9900dfce8
diff --git a/init/Android.mk b/init/Android.mk
index b02c926..c4f7d34 100644
--- a/init/Android.mk
+++ b/init/Android.mk
@@ -105,6 +105,10 @@
     libcap \
     libgsi \
     libcom.android.sysprop.apex \
+    liblzma \
+    libdexfile_support \
+    libunwindstack \
+    libbacktrace \
 
 LOCAL_SANITIZE := signed-integer-overflow
 # First stage init is weird: it may start without stdout/stderr, and no /proc.