Make linkerconfig support host

By supplying two additional args for host running
--root <root dir>
--vndk <vndk version>
one can run linkerconfig and see the resulting ld.config.txt

Some input files are found under <root>/system/etc with <vndk version>.
For example, out/target/vsoc_x86/system/etc/llndk.libraries.29.txt

Bug: 141660636
Test: m linkerconfig
Test: linkerconfig --root $OUT --vndk 29
Change-Id: I4aeab731a17764d7aa7e508842eae620f55f781e
4 files changed