Add new ld option: --print-memory-usage

Add new ld option: --print-memory-usage

ld/
	* NEWS: Mention new option.
	* lexsup.c (parse_args): Handle --print-memory-usage.
	(ld_options): Add --print-memory-usage.
	* ldmain.c (main): Call lang_print_memory_usage.
	* ldlex.h (enum option_values): Add OPTION_PRINT_MEMORY_USAGE.
	* ldlang.h: Add prototype of lang_print_memory_usage.
	* ldlang.c (lang_print_memory_size, lang_print_memory_usage): New
	functions.
	* ld.texinfo (Options): Document --print-memory-usage.
	* ld.h (args_type): Add print_memory_usage field.

ld/testsuite/
	* ld-scripts/print-memory-usage-1.t,
	* ld-scripts/print-memory-usage-1.s,
	* ld-scripts/print-memory-usage-1.l,
	* ld-scripts/print-memory-usage-2.t,
	* ld-scripts/print-memory-usage-2.l,
	* ld-scripts/print-memory-usage-3.s,
	* ld-scripts/print-memory-usage-3.t,
	* ld-scripts/print-memory-usage-3.l,
	* ld-scripts/print-memory-usage.t: New tests.
	* ld-scripts/print-memory-usage.exp: Run them.