objdump: Better objdump section headers in wide mode

objdump: Better objdump section headers in wide mode

When displaying the section headers table using objdump (-h), the column
containing the section header name is currently fixed at 13 characters.
A section name that is longer than 13 characters will overflow the
column causing the table to become miss-aligned.

In this commit I change the behaviour so that _in wide mode_ (-w -h) the
section name column is dynamically resized to fit the longest section
name we plan to display.  In wide mode the column still retains a
minimum width of 13 characters.

In non-wide more the behaviour is completely unchanged.

While I was changing the dump_headers function I have unified the two
printf lines that handled the different address widths into a single
printf, the address width is now passed into printf using the '*' field
width format character.

binutils/ChangeLog:

	* objdump.c (dump_section_header): Extract max section name length
	from data parameter, use this when formatting output.
	(find_longest_section_name): New function.
	(dump_headers): Calculate longest section name when in wide mode,
	reformat to unify printing of header line.

ld/ChangeLog:

	* testsuite/ld-elf/eh-frame-hdr.d: Update expected results.