x86: Add -z cet-report=[none|warning|error]

x86: Add -z cet-report=[none|warning|error]

Add -z cet-report=[none|warning|error] to report the missing Intel
Indirect Branch Tracking (IBT) and Shadow Stack (SHSTK) properties
in input .note.gnu.property section.  -z cet-report=none, which is
the default, will make the linker not report missing properties in
input files.  -z cet-report=warning will make the linker issue a
warning for missing properties in input files.  -z cet-report=error
will make the linker issue an error for missing properties in input
files.  Note that -z ibt will turn off the missing IBT property report
and -z shstk will turn off the missing SHSTK property report.
Supported for Linux/i386 and Linux/x86_64.

bfd/

	* elf-linker-x86.h (elf_x86_cet_report): New.
	(elf_linker_x86_params): Add cet_report.
	* elfxx-x86.c (_bfd_x86_elf_link_setup_gnu_properties): Report
	missing IBT and SHSTK properties if needed.

ld/

	* ld.texi: Document -z cet-report=[none|warning|error].
	* emulparams/cet.sh: Add -z cet-report=[none|warning|error].
	* testsuite/ld-i386/i386.exp: Run -z cet-report=[warning|error]
	tests.
	* testsuite/ld-x86-64/x86-64.exp: Likewise.
	* testsuite/ld-i386/property-x86-cet1.d: New file.
	* testsuite/ld-i386/property-x86-cet2a.d: Likewise.
	* testsuite/ld-i386/property-x86-cet2b.d: Likewise.
	* testsuite/ld-i386/property-x86-cet3a.d: Likewise.
	* testsuite/ld-i386/property-x86-cet3b.d: Likewise.
	* testsuite/ld-i386/property-x86-cet4a.d: Likewise.
	* testsuite/ld-i386/property-x86-cet4b.d: Likewise.
	* testsuite/ld-i386/property-x86-cet5a.d: Likewise.
	* testsuite/ld-i386/property-x86-cet5b.d: Likewise.
	* testsuite/ld-i386/property-x86-cet6.d: Likewise.
	* testsuite/ld-x86-64/property-x86-cet.s: Likewise.
	* testsuite/ld-x86-64/property-x86-cet1-x32.d: Likewise.
	* testsuite/ld-x86-64/property-x86-cet1.d: Likewise.
	* testsuite/ld-x86-64/property-x86-cet2a-x32.d: Likewise.
	* testsuite/ld-x86-64/property-x86-cet2a.d: Likewise.
	* testsuite/ld-x86-64/property-x86-cet2b-x32.d: Likewise.
	* testsuite/ld-x86-64/property-x86-cet2b.d: Likewise.
	* testsuite/ld-x86-64/property-x86-cet3a-x32.d: Likewise.
	* testsuite/ld-x86-64/property-x86-cet3a.d: Likewise.
	* testsuite/ld-x86-64/property-x86-cet3b-x32.d: Likewise.
	* testsuite/ld-x86-64/property-x86-cet3b.d: Likewise.
	* testsuite/ld-x86-64/property-x86-cet4a-x32.d: Likewise.
	* testsuite/ld-x86-64/property-x86-cet4a.d: Likewise.
	* testsuite/ld-x86-64/property-x86-cet4b-x32.d: Likewise.
	* testsuite/ld-x86-64/property-x86-cet4b.d: Likewise.
	* testsuite/ld-x86-64/property-x86-cet5a-x32.d: Likewise.
	* testsuite/ld-x86-64/property-x86-cet5a.d: Likewise.
	* testsuite/ld-x86-64/property-x86-cet5b-x32.d: Likewise.
	* testsuite/ld-x86-64/property-x86-cet5b.d: Likewise.
	* testsuite/ld-x86-64/property-x86-cet6-x32.d: Likewise.
	* testsuite/ld-x86-64/property-x86-cet6.d: Likewise.