Allow dlclose() to properly call static C++ destructors.

With this patch _and_ an upcoming build/ patch, the destruction
of static C++ objects contained in shared libraries will happen
properly when dlclose() is called.

Note that this change introduces crtbegin_so.S and crtend_so.S which
are currently ignored by the build system.

+ move definition of __dso_handle to the right place
(before that, all shared libraries used the __dso_handle
global variable from the C library).

Note that we keep a 'weak' __dso_handle in aeabi.c to avoid
breaking the build until the next patch to build/core/combo/
appears. We will be able to remove that later.

+ move bionic/aeabi.c to arch-arm/bionic/ (its proper location)

NOTE: The NDK will need to be modified to enable this feature in
         the shared libraries that are generated through it.

Change-Id: I99cd801375bbaef0581175893d1aa0943211b9bc
12 files changed