Fix --enable-gather-detailed-mem-stats build.

Fix --enable-gather-detailed-mem-stats build.

2018-01-12  Martin Liska  <mliska@suse.cz>

	* Makefile.in: As qsort_chk is implemented in vec.c, add
	vec.o to linkage of gencfn-macros.
	* tree.c (build_new_poly_int_cst): Add CXX_MEM_STAT_INFO as it's
	passing the info to record_node_allocation_statistics.
	(test_vector_cst_patterns): Add CXX_MEM_STAT_INFO to declaration
	and pass the info.
	* ggc-common.c (struct ggc_usage): Add operator== and use
	it in operator< and compare function.
	* mem-stats.h (struct mem_usage): Likewise.
	* vec.c (struct vec_usage): Remove operator< and compare
	function. Can be simply inherited.

From-SVN: r256582