PR gdb/14704:

	PR gdb/14704:
	* gdb_bfd.c (gdb_bfd_ref): Set BFD_DECOMPRESS.
	(zlib_decompress_section): Remove.
	(gdb_bfd_map_section): Only check for compressed section
	in mmap case.  Use bfd_get_full_section_contents.
	* osabi.c (check_note): Add 'sectsize' argument.  Read
	section data.
	(generic_elf_osabi_sniff_abi_tag_sections): Don't read
	section data.  Update for check_note change.
	* xcoffread.c (xcoff_initial_scan): Use
	bfd_get_full_section_contents.
	* py-auto-load.c (auto_load_section_scripts): Use
	bfd_get_full_section_contents.
	* contrib/cc-with-tweaks.sh: Add -Z option.
testsuite
	* gdb.base/comprdebug.exp: New file.