Add support for ASan odr_indicator.

Add support for ASan odr_indicator.

config/

        * bootstrap-asan.mk: Replace LSAN_OPTIONS=detect_leaks=0 with
        ASAN_OPTIONS=detect_leaks=0:use_odr_indicator=1.

gcc/

        * asan.c (asan_global_struct): Refactor.
        (create_odr_indicator): New function.
        (asan_needs_odr_indicator_p): Likewise.
        (is_odr_indicator): Likewise.
        (asan_add_global): Introduce odr_indicator_ptr. Pass it into global's
        constructor.
        (asan_protect_global): Do not protect odr indicators.

gcc/c-family/

	* c-attribs.c (asan odr indicator): New attribute.
	(handle_asan_odr_indicator_attribute): New function.

gcc/testsuite/

        * c-c++-common/asan/no-redundant-odr-indicators-1.c: New test.

From-SVN: r243153