Deprecate a.out support for NetBSD targets.

As discussed previously, a.out support is now quite deprecated, and in
some cases removed, in both Binutils itself and NetBSD, so this legacy
default makes little sense. `netbsdelf*` and `netbsdaout*` still work
allowing the user to be explicit about there choice. Additionally, the
configure script warns about the change as Nick Clifton requested.

One possible concern was the status of NetBSD on NS32K, where only a.out
was supported. But per [1] NetBSD has removed support, and if it were to
come back, it would be with ELF. The binutils implementation is
therefore marked obsolete, per the instructions in the last message.

With that patch and this one applied, I have confirmed the following:

--target=i686-unknown-netbsd
--target=i686-unknown-netbsdelf
  builds completely

--target=i686-unknown-netbsdaout
  properly fails because target is deprecated.

--target=vax-unknown-netbsdaout builds completely except for gas, where
the target is deprecated.

[1]: https://mail-index.netbsd.org/tech-toolchain/2021/07/19/msg004025.html
---
 bfd/config.bfd                             | 43 +++++++++++++--------
 bfd/configure.ac                           |  5 +--
 binutils/testsuite/binutils-all/nm.exp     |  2 +-
 binutils/testsuite/lib/binutils-common.exp |  7 +---
 config/picflag.m4                          |  4 +-
 gas/configure.tgt                          |  9 +++--
 gas/testsuite/gas/arm/blx-bl-convert.d     |  2 +-
 gas/testsuite/gas/arm/blx-local-thumb.d    |  2 +-
 gas/testsuite/gas/sh/basic.exp             |  2 +-
 gdb/configure.host                         | 34 +++++++----------
 gdb/configure.tgt                          |  2 +-
 gdb/testsuite/gdb.asm/asm-source.exp       |  6 +--
 intl/configure                             |  2 +-
 ld/configure.tgt                           | 44 +++++++++++-----------
 ld/testsuite/ld-arm/arm-elf.exp            |  4 +-
 ld/testsuite/ld-elf/elf.exp                |  2 +-
 ld/testsuite/ld-elf/shared.exp             |  4 +-
 libiberty/configure                        |  4 +-

3 files changed, 5 insertions, 5 deletions

diff --git a/ld/testsuite/ld-arm/arm-elf.exp b/ld/testsuite/ld-arm/arm-elf.exp
index 9bad9b8..e94a5b7 100644
--- a/ld/testsuite/ld-arm/arm-elf.exp
+++ b/ld/testsuite/ld-arm/arm-elf.exp
@@ -235,7 +235,7 @@ set tmp {
 	{{readelf -s script-type.sym}}
 	"script-type"}
 }
-if ![istarget "arm*-*-netbsdelf"] { append armelftests_common $tmp }
+if ![istarget "arm*-*-netbsd*"] { append armelftests_common $tmp }
 
 set tmp {
     {"callweak" "-static -T arm.ld" "" "" {callweak.s}
@@ -433,7 +433,7 @@ run_dump_test "pie-bind-locally"
 
 # Exclude non-ARM-EABI targets.
 
-if { [istarget "arm*-*-netbsdelf"] } {
+if { [istarget "arm*-*-netbsd*"] } {
     return
 }
 
diff --git a/ld/testsuite/ld-elf/elf.exp b/ld/testsuite/ld-elf/elf.exp
index e98bffc..01d22fa 100644
--- a/ld/testsuite/ld-elf/elf.exp
+++ b/ld/testsuite/ld-elf/elf.exp
@@ -304,7 +304,7 @@ set array_tests_static {
 }
 
 # NetBSD ELF systems do not currently support the .*_array sections.
-set xfails "*-*-netbsdelf*"
+set xfails "*-*-netbsd*"
 run_ld_link_exec_tests $array_tests $xfails
 
 if { [istarget *-*-linux*]
diff --git a/ld/testsuite/ld-elf/shared.exp b/ld/testsuite/ld-elf/shared.exp
index d00358e..4eb5fba 100644
--- a/ld/testsuite/ld-elf/shared.exp
+++ b/ld/testsuite/ld-elf/shared.exp
@@ -1124,7 +1124,7 @@ set run_tests [list \
 ]
 
 # NetBSD ELF systems do not currently support the .*_array sections.
-run_ld_link_exec_tests $run_tests "*-*-netbsdelf*"
+run_ld_link_exec_tests $run_tests "*-*-netbsd*"
 
 # These tests require dlopen support.
 set dlopen_run_tests [list \
@@ -1182,7 +1182,7 @@ if [check_libdl_available] {
   # Disable all sanitizers.
   set old_CFLAGS "$CFLAGS"
   append CFLAGS " $NOSANITIZE_CFLAGS"
-  run_ld_link_exec_tests $dlopen_run_tests "*-*-netbsdelf*"
+  run_ld_link_exec_tests $dlopen_run_tests "*-*-netbsd*"
   set CFLAGS "$old_CFLAGS"
 }