CleanSpec.mk

adbd has been built as a static executable since the same binary was
copied to the recovery partition where shared library is not supported.
However, since we now support shared library in the recovery partition,
adbd is built as a dynamic executable.

In addition, the dependency from adbd to libdebuggerd_handler is removed
as debuggerd is handled by the dynamic linker.

A few more modules in /system/core are marked as recovery_available:
true as they are transitive dependencies of the dynamic linker.

This change also includes ld.config.recovery.txt which is the linker
config file for the recovery mode. It is installed to /etc/ld.config.txt
and contains linker namespace config for the dynamic binaries under
/sbin.

Bug: 63673171
Test: `adb reboot recovery; adb devices` shows the device ID
Test: Select 'mount /system' in the recovery mode, then `adb shell`.
$ lsof -p `pidof adbd` shows that libm.so, libc.so, etc. are loaded from
the /lib directory.

Change-Id: I363d5a787863f1677ee40afb5d5841321ddaae77