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 +-

1 files changed, 28 insertions, 15 deletions

diff --git a/bfd/config.bfd b/bfd/config.bfd
index ebda78f60a7..606c9cea982 100644
--- a/bfd/config.bfd
+++ b/bfd/config.bfd
@@ -48,6 +48,7 @@ targ_underscore=no
 
 # Catch obsolete configurations.
 case $targ in
+ ns32k-*-netbsd* | \
  null)
     if test "x$enable_obsolete" != xyes; then
       echo "*** Configuration $targ is obsolete." >&2
@@ -58,8 +59,19 @@ case $targ in
     fi;;
 esac
 
+# Warn on changed defaulting
+case $targ in
+ *-*-netbsdelf* | *-*-netbsdaout* | *-*-netbsdpe*)
+    # Explicit, no defaulting
+    ;;
+ *-*-netbsd* )
+    targ_migrated=`echo "$targ" | sed 's/netbsd/netbsdaout/'`
+    echo "*** WARNING: $targ is now defaults to meaning ELF not a.out." >&2
+    echo "*** Use $targ_migrated instead to explicitly specify a.out." >&2
+    ;;
+esac
+
 case $targ in
- *-*-netbsdelf* | i[3-7]86-*-netbsd*-gnu* | i[3-7]86-*-knetbsd*-gnu | \
  mips*-*-irix5* | mips*-*-irix6*)
     # Not obsolete
     ;;
@@ -75,7 +87,7 @@ case $targ in
  a29k-* | \
  arm*-*-aout | \
  arm-*-coff | \
- arm-*-netbsd* | \
+ arm*-*-netbsdaout* | \
  arm-*-openbsd* | \
  arm-*-oabi | \
  arm-*-riscix* | \
@@ -96,7 +108,7 @@ case $targ in
  i[3-7]86-*-aix* | \
  i[3-7]86-sequent-bsd* | \
  i[3-7]86-*-freebsdaout* | i[3-7]86-*-freebsd[12].* | i[3-7]86-*-freebsd[12] | \
- i[3-7]86-*-netbsdaout* | i[3-7]86-*-netbsd* | \
+ i[3-7]86-*-netbsdaout* | \
  i[3-7]86-*-openbsd[0-2].* | i[3-7]86-*-openbsd3.[0-3] | \
  i[3-7]86-*-linux*aout* | \
  i[3-7]86-*-mach* | i[3-7]86-*-osf1mk* | \
@@ -141,6 +153,7 @@ case $targ in
  or32-*-* | \
  powerpc-*-lynxos* | powerpc-*-windiss* | \
  powerpcle-*-pe | powerpcle-*-winnt* | powerpcle-*-cygwin* | \
+ sh*-*-netbsdaout* | \
  sh*-*-symbianelf* | sh5*-*-* | sh64*-*-* | \
  sparc*-*-*aout* | \
  sparc*-*-chorus* | \
@@ -345,11 +358,11 @@ case "${targ}" in
     targ_defvec=arm_elf32_nacl_be_vec
     targ_selvecs="arm_elf32_nacl_le_vec"
     ;;
-  armeb-*-netbsdelf*)
+  armeb-*-netbsd*)
     targ_defvec=arm_elf32_be_vec
     targ_selvecs="arm_elf32_le_vec"
     ;;
-  arm-*-netbsdelf*)
+  arm-*-netbsd*)
     targ_defvec=arm_elf32_le_vec
     targ_selvecs="arm_elf32_be_vec"
     ;;
@@ -609,7 +622,7 @@ case "${targ}" in
 	targ_cflags=-DOLD_FREEBSD_ABI_LABEL ;;
     esac
     ;;
-  i[3-7]86-*-netbsdelf* | i[3-7]86-*-netbsd*-gnu* | i[3-7]86-*-knetbsd*-gnu)
+  i[3-7]86-*-netbsd* | i[3-7]86-*-knetbsd*-gnu)
     targ_defvec=i386_elf32_vec
     targ_selvecs="iamcu_elf32_vec"
     targ64_selvecs="x86_64_elf64_vec l1om_elf64_vec k1om_elf64_vec"
@@ -983,7 +996,7 @@ case "${targ}" in
     targ_defvec=ns32k_aout_pc532mach_vec
     targ_underscore=yes
     ;;
-  ns32k-*-netbsd* | ns32k-*-lites* | ns32k-*-openbsd*)
+  ns32k-*-lites* | ns32k-*-openbsd*)
     targ_defvec=ns32k_aout_pc532nbsd_vec
     targ_underscore=yes
     ;;
@@ -1222,11 +1235,11 @@ case "${targ}" in
     targ_selvecs="sh_elf32_le_vec sh_elf32_linux_be_vec sh_elf32_linux_vec sh_elf32_fdpic_le_vec sh_elf32_fdpic_be_vec"
     ;;
 
-  sh*l*-*-netbsdelf*)
+  sh*l*-*-netbsd*)
     targ_defvec=sh_elf32_nbsd_le_vec
     targ_selvecs="sh_elf32_nbsd_vec sh_coff_vec sh_coff_le_vec"
     ;;
-  sh*-*-netbsdelf*)
+  sh*-*-netbsd*)
     targ_defvec=sh_elf32_nbsd_vec
     targ_selvecs="sh_elf32_nbsd_le_vec sh_coff_vec sh_coff_le_vec"
     ;;
@@ -1345,17 +1358,17 @@ case "${targ}" in
     targ_underscore=yes
     ;;
 
-  vax-*-netbsdelf*)
-    targ_defvec=vax_elf32_vec
-    targ_selvecs="vax_aout_nbsd_vec vax_aout_1knbsd_vec"
-    ;;
-
-  vax-*-netbsdaout* | vax-*-netbsd*)
+  vax-*-netbsdaout*)
     targ_defvec=vax_aout_nbsd_vec
     targ_selvecs="vax_elf32_vec vax_aout_1knbsd_vec"
     targ_underscore=yes
     ;;
 
+  vax-*-netbsd*)
+    targ_defvec=vax_elf32_vec
+    targ_selvecs="vax_aout_nbsd_vec vax_aout_1knbsd_vec"
+    ;;
+
   vax-*-openbsd*)
     targ_defvec=vax_aout_nbsd_vec
     targ_underscore=yes