Add support for x86_64-*-gnu-* targets to build x86_64 gnumach/hurd

bfd/config.bfd

@@ -731,6 +731,11 @@ case "${targ}" in
     targ_selvecs=i386_elf32_vec
     want64=true
     ;;
+  x86_64-*-gnu*)
+    targ_defvec=x86_64_elf64_vec
+    targ_selvecs="i386_elf32_vec iamcu_elf32_vec x86_64_elf32_vec"
+    want64=true
+    ;;
 #endif
   i[3-7]86-*-lynxos*)
     targ_defvec=i386_elf32_vec

ld/configure.tgt

@@ -1058,6 +1058,11 @@ x86_64-*-mingw*)	targ_emul=i386pep ;
 			targ_extra_emuls=i386pe
 			targ_extra_ofiles="deffilep.o pdb.o pep-dll.o pe-dll.o"
 			;;
+x86_64-*-gnu*)		targ_emul=elf_x86_64
+			targ_extra_emuls="elf32_x86_64 elf_iamcu elf_i386"
+			targ_extra_libpath="elf_i386 elf32_x86_64"
+			tdir_elf_i386=`echo ${targ_alias} | sed -e 's/x86_64/i386/'`
+			;;
 xgate-*-*)		targ_emul=xgateelf
 			targ_extra_ofiles=ldelfgen.o
 			;;