Unhide rtld_db_dlactivity()

Since linker is built with -fvisibility=hidden rtld_db_dlactivity()
if hidden from gdb.  Unhide it otherwise gdb may not know linker
activity and rescan solib

Change-Id: Ia8cd8d9738c6ea5696ba2ef0ebf2cf783f9ca70a
merge in jb-mr0-release history after reset to jb-dev
Merge android-4.1.2_r1
Do not include '\0' when writing error messages to stderr

Change-Id: I6adc806c3920e5a4ae61ca55c40613fcf338b18c
Verify architecture neutral syscall numbers

Also removed some dead code and fixed comment

Change-Id: I5d6a04b4af3d95e34368136cf2eeb3c9b6f99769
Signed-off-by: Chris Dearman <chris@mips.com>