PR middle-end/64937
	* dwarf2out.c (set_block_abstract_flags, set_decl_abstract_flags):
	Replace setting argument with abstract_vec, always set BLOCK_ABSTRACT
	or DECL_ABSTRACT_P flags to 1 rather than to setting, and if it wasn't
	1 before, push it to abstract_vec.
	(dwarf2out_abstract_function): Adjust caller.  Don't call
	set_decl_abstract_flags second time, instead clear BLOCK_ABSTRACT or
	DECL_ABSTRACT_P flags for all abstract_vec elts.

	* g++.dg/asan/pr64937.C: New test.

From-SVN: r220483