Sync linker with internal branch

This change includes dlwarning implementation and
the compatibility greylist for apps targeting pre-N.

Change-Id: Ibf02a07cc58cbbb1a5aef4ac34558c5d43e4305f
Test: Run bionic-unit-tests --gtest_filter=dl*:Dl*
diff --git a/linker/Android.bp b/linker/Android.bp
index d7e97f0..a35eb45 100644
--- a/linker/Android.bp
+++ b/linker/Android.bp
@@ -18,6 +18,7 @@
         "dlfcn.cpp",
         "linker.cpp",
         "linker_block_allocator.cpp",
+        "linker_dlwarning.cpp",
         "linker_gdb_support.cpp",
         "linker_libc_support.c",
         "linker_logger.cpp",