MIPS: Support `-gnuabi64' target triplet suffix for 64-bit Linux targets

Make the n64 ABI the default for 64-bit Linux targets specified with
`-gnuabi64' suffix included in the target triplet, for configurations
such as the Debian mips64el and mips64r6el ports.  Adjust testsuite
configuration accordingly.

There are the following regressions with the new target triplet:

mips64-linux-gnuabi64  +FAIL: readelf -S bintest
mips64-linux-gnuabi64  +FAIL: MIPS reloc estimation 1
mips64el-linux-gnuabi64  +FAIL: readelf -S bintest
mips64el-linux-gnuabi64  +FAIL: MIPS reloc estimation 1

The `readelf' issue comes from a difference in section headers produced
that the `binutils/testsuite/binutils-all/readelf.s-64' pattern template
does not match.  While there has been a precedent it does not appear to
me that there is a clear advantage from adding more and more variations
to the template rather than forking the existing template into multiple
ones for a more exact match.  So this is best deferred to a separate
discussion.

The MIPS reloc estimation issue is an actual bug in `objdump', which
discards a number of trailing entries from output here for n64 composed
relocations:

DYNAMIC RELOCATION RECORDS
OFFSET           TYPE              VALUE
0000000000000000 R_MIPS_NONE       *ABS*
0000000000000000 R_MIPS_NONE       *ABS*

and consequently `ld/testsuite/ld-mips-elf/reloc-estimate-1.d' does not
match even though ELF output produced is correct according to `readelf':

Relocation section '.rel.dyn' at offset 0x10400 contains 2 entries:
  Offset          Info           Type           Sym. Value    Sym. Name
000000000000  000000000000 R_MIPS_NONE
                    Type2: R_MIPS_NONE
                    Type3: R_MIPS_NONE
000000010000  000300001203 R_MIPS_REL32      0000000000010010 foo@@V2
                    Type2: R_MIPS_64
                    Type3: R_MIPS_NONE

As a genuine bug this has to be handled separately.

Co-Authored by: Maciej W. Rozycki <macro@orcam.me.uk>

	bfd/
	* config.bfd: Add `mips64*el-*-linux*-gnuabi64' and
	`mips64*-*-linux*-gnuabi64' targets.

	binutils/
	* testsuite/binutils-all/mips/mips.exp: Handle `*-*-*-gnuabi64'
	targets.
	* testsuite/binutils-all/objcopy.exp: Handle
	`mips64*-*-*-gnuabi64' targets.
	* testsuite/binutils-all/remove-relocs-01.d: Likewise.
	* testsuite/binutils-all/remove-relocs-04.d: Likewise.
	* testsuite/binutils-all/remove-relocs-05.d: Likewise.
	* testsuite/binutils-all/remove-relocs-06.d: Likewise.

	gas/
	* configure.ac: Handle `mips64*-linux-gnuabi64' targets.
	* configure: Regenerate.
	* testsuite/gas/mips/compact-eh-eb-7.d: Handle
	`mips64*-*-*-gnuabi64' targets.
	* testsuite/gas/mips/compact-eh-el-7.d: Likewise.

	ld/
	* configure.tgt: Add `mips64*el-*-linux-gnuabi64' and
	`mips64*-*-linux-gnuabi64' targets.
	* testsuite/ld-undefined/undefined.exp: Handle
	`mips64*-*-*-gnuabi64' targets.
	* testsuite/ld-mips-elf/attr-gnu-4-10.d: Likewise.
	* testsuite/ld-mips-elf/compact-eh6.d: Likewise.
	* testsuite/ld-mips-elf/mips-elf.exp: Handle `*-*-*-gnuabi64'
	targets.

3 files changed, 18 insertions, 7 deletions

diff --git a/ld/testsuite/ld-mips-elf/attr-gnu-4-10.d b/ld/testsuite/ld-mips-elf/attr-gnu-4-10.d
index 2ddb3d3..fe39ece 100644
--- a/ld/testsuite/ld-mips-elf/attr-gnu-4-10.d
+++ b/ld/testsuite/ld-mips-elf/attr-gnu-4-10.d
@@ -3,7 +3,7 @@
 #as: -mpdr
 #ld: -r
 #readelf: -hA
-#notarget: mips64*-*-openbsd*
+#notarget: mips64*-*-openbsd* mips64*-*-*-gnuabi64
 
 ELF Header:
   Magic:   .*
diff --git a/ld/testsuite/ld-mips-elf/compact-eh6.d b/ld/testsuite/ld-mips-elf/compact-eh6.d
index e81285a..a4a6978 100644
--- a/ld/testsuite/ld-mips-elf/compact-eh6.d
+++ b/ld/testsuite/ld-mips-elf/compact-eh6.d
@@ -4,7 +4,7 @@
 #as: -EB
 #readelf: -x .eh_frame_hdr
 #ld: -EB -e main
-#
+#notarget: mips64*-*-*-gnuabi64
 
 Hex dump of section \'\.eh_frame_hdr\':
 
diff --git a/ld/testsuite/ld-mips-elf/mips-elf.exp b/ld/testsuite/ld-mips-elf/mips-elf.exp
index 8be2bfc..e123ef5 100644
--- a/ld/testsuite/ld-mips-elf/mips-elf.exp
+++ b/ld/testsuite/ld-mips-elf/mips-elf.exp
@@ -155,13 +155,23 @@ if {[istarget *-*-openbsd*] } {
     if [istarget *el-*-*] {
 	set abi_asflags(o32) -32
 	set abi_ldflags(o32) -melf32ltsmip
-	set abi_asflags(n64) "-march=from-abi -64"
-	set abi_ldflags(n64) -melf64ltsmip
+	if [istarget *-*-*-gnuabi64] {
+	    set abi_asflags(n32) "-march=from-abi -n32"
+	    set abi_ldflags(n32) -melf32ltsmipn32
+	} else {
+	    set abi_asflags(n64) "-march=from-abi -64"
+	    set abi_ldflags(n64) -melf64ltsmip
+	}
     } else {
 	set abi_asflags(o32) -32
 	set abi_ldflags(o32) -melf32btsmip
-	set abi_asflags(n64) "-march=from-abi -64"
-	set abi_ldflags(n64) -melf64btsmip
+	if [istarget *-*-*-gnuabi64] {
+	    set abi_asflags(n32) "-march=from-abi -n32"
+	    set abi_ldflags(n32) -melf32btsmipn32
+	} else {
+	    set abi_asflags(n64) "-march=from-abi -64"
+	    set abi_ldflags(n64) -melf64btsmip
+	}
     }
     set irixemul 0
 } elseif {[istarget *-*-linux*] } {
@@ -811,7 +821,8 @@ if { $linux_gnu } {
     run_dump_test "got-page-1"
     run_dump_test_n32 "got-page-2"
     run_dump_test_n64 "dyn-sec64" noarch
-    run_dump_test "got-page-3"
+    run_dump_test_o32 "got-page-3"
+    run_dump_test_n32 "got-page-3" [list [list name (n32)]]
     if $has_abi(o32) {
 	run_ld_link_tests [subst {
 	    {"GOT page 4 (one file)"