GN: Change extension of debug pexe builds from .pexe-debug to .pexe.debug

build/toolchain/nacl/BUILD.gn

 # Copyright (c) 2014 The Native Client Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/sysroot.gni")
 import("//build/toolchain/nacl_toolchain.gni")
 
 nacl_toolchain_dir = rebase_path("//native_client/toolchain", root_build_dir)
 os_toolchain_dir = "${nacl_toolchain_dir}/${current_os}_x86"
 
@@ skipping 56 matching lines @@
 nacl_toolchain("newlib_pnacl") {
   toolchain_package = "pnacl_newlib"
   toolchain_revision = pnacl_newlib_rev
   toolchain_cpu = "pnacl"
   toolprefix = "${os_toolchain_dir}/${toolchain_package}/bin/pnacl-"
 
   cc = toolprefix + "clang"
   cxx = toolprefix + "clang++"
   ar = toolprefix + "ar"
   ld = cxx
-  executable_extension = ".pexe-debug"
+  executable_extension = ".pexe.debug"
 
   finalize = toolprefix + "finalize"
   nonfinal_file =
       "{{root_out_dir}}/{{target_output_name}}${executable_extension}"
   finalized_file = "{{root_out_dir}}/{{target_output_name}}.pexe"
   postlink = "$finalize $nonfinal_file -o $finalized_file"
   link_outputs = [ finalized_file ]
 }
 
 nacl_toolchain("glibc_x86") {
@@ skipping 106 matching lines @@
 
   # Some IRT implementations (notably, Chromium's) contain C++ code,
   # so we need to link w/ the C++ linker.
   ld = "${python_path} ${link_irt} --tls-edit=tls_edit --link-cmd=${cxx} --readelf-cmd=${readelf}"
 
   # TODO(ncbray): depend on link script
   deps = [
     "//native_client/src/tools/tls_edit:tls_edit($host_toolchain)",
   ]
 }