Ensure libgcc_s unwinder is always used on 64-bit Solaris 10+/x86 (PR target/59788)

Ensure libgcc_s unwinder is always used on 64-bit Solaris 10+/x86 (PR target/59788)

	gcc:
	PR target/59788
	* config/sol2.h (LINK_LIBGCC_MAPFILE_SPEC): Define.
	(LINK_SPEC): Use it for -shared, -shared-libgcc.

	libgcc:
	PR target/59788
	* config/t-slibgcc-sld (libgcc-unwind.map): New target.
	(install-libgcc-unwind-map-forbuild): New target.
	(all): Depend on install-libgcc-unwind-map-forbuild.
	(install-libgcc-unwind-map): New target.
	(install): Depend on install-libgcc-unwind-map.

	gcc/testsuite:
	PR target/59788
	* g++.dg/eh/unwind-direct.C: New test.

	toplevel:
	PR target/59788
	* ltmain.sh (opt_duplicate_compiler_generated_deps): Enable on
	*solaris2*.

From-SVN: r207454