Import patches from the master branch which prevent seg-faults when parsing

Import patches from the master branch which prevent seg-faults when parsing
corrupt binaries.

	2014-10-28  Andreas Schwab  <schwab@suse.de>
		    Nick Clifton  <nickc@redhat.com>
	PR binutils/17510
	* srec.c (srec_bad_byte): Increase size of buf to allow for
	negative values.
	(srec_scan): Use an unsigned char buffer to hold header bytes.

	2014-10-27  Nick Clifton  <nickc@redhat.com>
	PR binutils/17512
	* elf.c (bfd_section_from_shdr): Detect and warn about ELF
	binaries with a group of sections linked by the string table
	indicies.
	* peXXigen.c (_bfd_XXi_swap_aouthdr_in): Handle corrupt binaries
	with an invalid value for NumberOfRvaAndSizes.
	(pe_print_edata): Detect out of range rvas and entry counts for
	the Export Address table, Name Pointer table and Ordinal table.

	PR binutils/17510
	* elf.c (setup_group): Improve handling of corrupt group
	sections.