Subzero. Adds x86-64 to the list of supported Subzero targets.

toolchain_build/toolchain_build_pnacl.py

Index: toolchain_build/toolchain_build_pnacl.py
diff --git a/toolchain_build/toolchain_build_pnacl.py b/toolchain_build/toolchain_build_pnacl.py
index 025a67b8e820059bbc48225965a7120efe416ef6..8e53e69109abc598c4bdb27fe214a493acb3d68d 100755
--- a/toolchain_build/toolchain_build_pnacl.py
+++ b/toolchain_build/toolchain_build_pnacl.py
@@ -688,7 +688,7 @@ def HostTools(host, options):
                   '-DLLVM_EXTERNAL_SUBZERO_SOURCE_DIR=%(subzero_src)s',
                   '-DLLVM_INSTALL_UTILS=ON',
                   '-DLLVM_TARGETS_TO_BUILD=X86;ARM;Mips;JSBackend',
-                  '-DSUBZERO_TARGETS_TO_BUILD=X8632;ARM32;MIPS32',
+                  '-DSUBZERO_TARGETS_TO_BUILD=ARM32;MIPS32;X8632;X8664',
                   '%(llvm_src)s'],
                   # Older CMake ignore CMAKE_*_LINKER_FLAGS during config step.
                   # https://public.kitware.com/Bug/view.php?id=14066
@@ -734,7 +734,7 @@ def HostTools(host, options):
                    '--enable-debug=' + ('yes' if HostIsDebug(options)
                                         else 'no'),
                    '--enable-targets=x86,arm,mips,js',
-                   '--enable-subzero-targets=X8632,ARM32,MIPS32',
+                   '--enable-subzero-targets=ARM32,MIPS32,X8632,X8664',
                    '--enable-werror=' + ('yes' if llvm_do_werror else 'no'),
                    # Backtraces require TLS, which is missing on OSX 10.6
                    '--enable-backtraces=' + ('no' if TripleIsMac(host)