Configure gdb for nacl target

bfd/config.bfd

 # config.bfd
 # Convert a canonical host type into a BFD host type.
 # Set shell variable targ to canonical target name, and run
 # using ``. config.bfd''.
 # Sets the following shell variables:
 #  targ_defvec          Default vector for this target
 #  targ_selvecs         Vectors to build for this target
 #  targ64_selvecs       Vectors to build if --enable-64-bit-bfd is given
 #                       or if host is 64 bit.
 #  targ_archs           Architectures for this target
@@ skipping 588 matching lines @@
   x86_64-*-freebsd* | x86_64-*-kfreebsd*-gnu)
     targ_defvec=bfd_elf64_x86_64_freebsd_vec
     targ_selvecs="bfd_elf32_i386_freebsd_vec i386coff_vec i386pei_vec x86_64pei_vec bfd_elf32_i386_vec bfd_elf64_x86_64_vec bfd_elf64_l1om_vec bfd_elf64_l1om_freebsd_vec bfd_elf64_k1om_vec bfd_elf64_k1om_freebsd_vec"
     want64=true
     ;;
   x86_64-*-netbsd* | x86_64-*-openbsd*)
     targ_defvec=bfd_elf64_x86_64_vec
     targ_selvecs="bfd_elf32_i386_vec i386netbsd_vec i386coff_vec i386pei_vec x86_64pei_vec bfd_elf64_l1om_vec bfd_elf64_k1om_vec"
     want64=true
     ;;
-  x86_64-*-linux-*)
+  x86_64-*-linux-* | x86_64-*-nacl*)
     targ_defvec=bfd_elf64_x86_64_vec
     targ_selvecs="bfd_elf32_i386_vec bfd_elf32_x86_64_vec i386linux_vec i386pei_vec x86_64pei_vec bfd_elf64_l1om_vec bfd_elf64_k1om_vec"
     want64=true
     ;;
   x86_64-*-mingw* | x86_64-*-pe | x86_64-*-pep)
     targ_defvec=x86_64pe_vec
     targ_selvecs="x86_64pe_vec x86_64pei_vec bfd_elf64_x86_64_vec bfd_elf64_l1om_vec bfd_elf64_k1om_vec i386pe_vec i386pei_vec bfd_elf32_i386_vec"
     want64=true
     targ_underscore=no
     ;;
@@ skipping 1005 matching lines @@
     targ_archs="$targ_archs bfd_l1om_arch"
     ;;
 esac
 
 # If we support Intel K1OM target, then add support for bfd_k1om_arch.
 case "${targ_defvec} ${targ_selvecs}" in
   *bfd_elf64_k1om_vec*)
     targ_archs="$targ_archs bfd_k1om_arch"
     ;;
 esac