Be clearer about linker warnings.

Explicitly say "warning" for warnings, explicitly say what action
we're going to take (such as "(ignoring)"), always provide a link to
our documentation when there is one, explicitly say what API level the
behavior changes at, and explicitly say why we're allowing the misbehavior
for now.

Bug: http://b/71852862
Test: ran tests, looked at logcat
Change-Id: I1795a5af45deb904332b866d7d666690dae4340b
diff --git a/linker/linker_soinfo.cpp b/linker/linker_soinfo.cpp
index 54bfcf0..731e8f5 100644
--- a/linker/linker_soinfo.cpp
+++ b/linker/linker_soinfo.cpp
@@ -152,7 +152,7 @@
       ELF_ST_BIND(s->st_info) == STB_WEAK) {
     return s->st_shndx != SHN_UNDEF;
   } else if (ELF_ST_BIND(s->st_info) != STB_LOCAL) {
-    DL_WARN("unexpected ST_BIND value: %d for \"%s\" in \"%s\"",
+    DL_WARN("Warning: unexpected ST_BIND value: %d for \"%s\" in \"%s\" (ignoring)",
             ELF_ST_BIND(s->st_info), si->get_string(s->st_name), si->get_realpath());
   }