Add option to nm to change the characters displayed for ifunc symbols. Add a configu...

Add option to nm to change the characters displayed for ifunc symbols.  Add a configure time option to change the default characters.

	PR 22967
	* nm.c (ifunc_type_chars): New variable.
	(long_options): Add --ifunc-chars.
	(print_symbol): Use ifunc_type_chars for ifunc symbols.
	(main): Handle the new option.
	* doc/binutils.texi: Document the new option.
	* configure.ac: Add --enable-f-for-ifunc-symbols option which
	changes the default symbol displayed by nm.
	* NEWS: Mention the new feature.
	* testsuite/binutils-all/nm.exp: Test the new feature.
	* config.in: Regenerate.
	* configure: Regenerate.