enable-non-contiguous-regions warnings

enable-non-contiguous-regions warnings

The warning about discarded sections in elf_link_input_bfd doesn't
belong there since the code is dealing with symbols.  Multiple symbols
in a discarded section will result in multiple identical warnings
about the section.  Move the warning to a new function in ldlang.c.

The patch also tidies the warning quoting of section and file names,
consistently using `%pA' and `%pB'.  I'm no stickler for one style of
section and file name quoting, but they ought to be consistent within
a warning, eg. see the first one fixed in ldlang.c, and when a warning
is emitted for multiple targets they all ought to use exactly the same
format string to reduce translation work.  elf64-ppc.c loses the
build_one_stub errors since we won't get there before hitting the
fatal errors in size_one_stub.

bfd/
	* elflink.c (elf_link_input_bfd): Don't warn here about
	discarded sections.
	* elf32-arm.c (arm_build_one_stub): Use consistent style in
	--enable-non-contiguous-regions error.
	* elf32-csky.c (csky_build_one_stub): Likewise.
	* elf32-hppa.c (hppa_build_one_stub): Likewise.
	* elf32-m68hc11.c (m68hc11_elf_build_one_stub): Likewise.
	* elf32-m68hc12.c (m68hc12_elf_build_one_stub): Likewise.
	* elf32-metag.c (metag_build_one_stub): Likewise.
	* elf32-nios2.c (nios2_build_one_stub): Likewise.
	* elfnn-aarch64.c (aarch64_build_one_stub): Likewise.
	* xcofflink.c (xcoff_build_one_stub): Likewise.
	* elf64-ppc.c (ppc_size_one_stub): Likewise.
	(ppc_build_one_stub): Delete dead code.
ld/
	* ldlang.c (lang_add_section): Use consistent style in
	--enable-non-contiguous-regions warnings.
	(size_input_section): Likewise.
	(warn_non_contiguous_discards): New function.
	(lang_process): Call it.
	* testsuite/ld-arm/non-contiguous-arm.d: Update.
	* testsuite/ld-arm/non-contiguous-arm4.d: Update.
	* testsuite/ld-arm/non-contiguous-arm7.d: Add
	--enable-non-contiguous-regions-warnings.
	* testsuite/ld-arm/non-contiguous-arm7.err: New.
	* testsuite/ld-powerpc/non-contiguous-powerpc.d: Update.
	* testsuite/ld-powerpc/non-contiguous-powerpc64.d: Update.