GN: Change the default meaning of dart_target_arch from current_cpu to target_cpu.

runtime/BUILD.gn

 # Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 import("runtime_args.gni")
 
 config("dart_public_config") {
   include_dirs = [ "." ]
 }
 
@@ skipping 46 matching lines @@
     defines += [ "TARGET_OS_LINUX" ]
   } else if (target_os == "mac") {
     defines += [ "TARGET_OS_MACOS" ]
   } else if (target_os == "win") {
     defines += [ "TARGET_OS_WINDOWS" ]
   } else {
     print("Unknown target_os: $target_os")
     assert(false)
   }
 
-  if (dart_target_arch != "") {
-    if (dart_target_arch == "arm" || dart_target_arch == "simarm") {
-      defines += [ "TARGET_ARCH_ARM" ]
-    } else if (dart_target_arch == "armv6" || dart_target_arch == "simarmv6") {
-      defines += [ "TARGET_ARCH_ARM" ]
-      defines += [ "TARGET_ARCH_ARM_6" ]
-    } else if (dart_target_arch == "armv5te" ||
-               dart_target_arch == "simarmv5te") {
-      defines += [ "TARGET_ARCH_ARM" ]
-      defines += [ "TARGET_ARCH_ARM_5TE" ]
-    } else if (dart_target_arch == "arm64" || dart_target_arch == "simarm64") {
-      defines += [ "TARGET_ARCH_ARM64" ]
-    } else if (dart_target_arch == "x64") {
-      defines += [ "TARGET_ARCH_X64" ]
-    } else if (dart_target_arch == "ia32") {
-      defines += [ "TARGET_ARCH_IA32" ]
-    } else if (dart_target_arch == "dbc" || dart_target_arch == "simdbc" ||
-               dart_target_arch == "simdbc64" ||
-               dart_target_arch == "armsimdbc" ||
-               dart_target_arch == "armsimdbc64") {
-      defines += [ "TARGET_ARCH_DBC" ]
-      defines += [ "USING_SIMULATOR" ]
-    } else {
-      print("Invalid dart_target_arch: $dart_target_arch")
-      assert(false)
-    }
+  if (dart_target_arch == "arm") {
+    defines += [ "TARGET_ARCH_ARM" ]
+  } else if (dart_target_arch == "armv6") {
+    defines += [ "TARGET_ARCH_ARM" ]
+    defines += [ "TARGET_ARCH_ARM_6" ]
+  } else if (dart_target_arch == "armv5te") {
+    defines += [ "TARGET_ARCH_ARM" ]
+    defines += [ "TARGET_ARCH_ARM_5TE" ]
+  } else if (dart_target_arch == "arm64") {
+    defines += [ "TARGET_ARCH_ARM64" ]
+  } else if (dart_target_arch == "x64") {
+    defines += [ "TARGET_ARCH_X64" ]
+  } else if (dart_target_arch == "ia32" || dart_target_arch == "x86") {
+    defines += [ "TARGET_ARCH_IA32" ]
+  } else if (dart_target_arch == "dbc") {
+    defines += [ "TARGET_ARCH_DBC" ]
+    defines += [ "USING_SIMULATOR" ]
+  } else {
+    print("Invalid dart_target_arch: $dart_target_arch")
+    assert(false)
   }
 
   if (dart_debug) {
     defines += [ "DEBUG" ]
   } else {
     defines += [ "NDEBUG" ]
   }
 
   include_dirs = []
   if (dart_use_tcmalloc) {
@@ skipping 149 matching lines @@
 
   script = "../tools/make_version.py"
   args = [
     "--quiet",
     "--output",
     rebase_path(output, root_build_dir),
     "--input",
     rebase_path("vm/version_in.cc", root_build_dir),
   ]
 }