(COLLECT_SHARD_FINI_FUNC): Define default values.
(write_c_file_stat): Use them to call construtor and destructor
functions in shared libraries.
* doc/tm.texi (COLLECT_SHARED_INIT_FUNC)
(COLLECT_SHARD_FINI_FUNC): Document them.
* config/netbsd.h (COLLECT_SHARED_INIT_FUNC)
(COLLECT_SHARD_FINI_FUNC): Define.

* config/netbsd.h (LINK_SPEC): Don't pull in estart if creating a
shared library.  Pass -shared through to the linker.
* config/arm/netbsd.h (LINK_SPEC): Likewise.

* config/arm/t-netbsd (TARGET_LIBGCC2_CFLAGS): Add -fpic.
(SHLIB_EXT, SHLIB_NAME, SHLIB_SONAME, SHLIB_OBJS, SHLIB_LINK)
(SHLIB_INSTALL): Define.

From-SVN: r47975