Darwin: Match system sections and relocs for exception tables.

Darwin: Match system sections and relocs for exception tables.

System tools from Darwin10 onwards have moved the exceptions tables from
the __DATA segment to the __TEXT one.  They also revised the relocations
used for typeinfo.  While Darwin9 was not changed at the time, in fact the
tools there are equally happy with the revised scheme - and therefore at
present there seems no reason to special-case it.

Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>
gcc/ChangeLog:

	* config/darwin-sections.def (darwin_exception_section): Move to
	the __TEXT segment.
	* config/darwin.cc (darwin_emit_except_table_label): Align before
	the exception table label.
	* config/darwin.h (ASM_PREFERRED_EH_DATA_FORMAT): Use indirect PC-
	relative 4byte relocs.

(cherry picked from commit 0fe7962afc7c01488432b98b6f442b24946a490d)