Set TARGET_OS_* from GN, falling back to HOST_OS_*.

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")
 
 declare_args() {
   # Instead of using is_debug, we introduce a different flag for specifying a
   # Debug build of Dart so that clients can still use a Release build of Dart
   # while themselves doing a Debug build.
@@ skipping 90 matching lines @@
   defines += [ "DART_NO_SNAPSHOT" ]
 }
 
 config("dart_config") {
   defines = []
 
   if (dart_experimental_interpreter) {
     dart_target_arch = "dbc"
   }
 
+  if (target_os == "android") {
+    defines += [ "TARGET_OS_ANDROID" ]
+  } else if (target_os == "fuchsia") {
+    defines += [ "TARGET_OS_FUCHSIA" ]
+  } else if (target_os == "ios") {
+    defines += [ "TARGET_OS_MACOS" ]
+    defines += [ "TARGET_OS_MACOS_IOS" ]
+  } else if (target_os == "linux") {
+    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" ]
-      if (target_os == "mac" || target_os == "ios") {
-        defines += [ "TARGET_ABI_IOS" ]
-      } else {
-        defines += [ "TARGET_ABI_EABI" ]
-      }
     } else if (dart_target_arch == "armv6" || dart_target_arch == "simarmv6") {
       defines += [ "TARGET_ARCH_ARM" ]
       defines += [ "TARGET_ARCH_ARM_6" ]
-      defines += [ "TARGET_ABI_EABI" ]
     } else if (dart_target_arch == "armv5te" ||
                dart_target_arch == "simarmv5te") {
       defines += [ "TARGET_ARCH_ARM" ]
       defines += [ "TARGET_ARCH_ARM_5TE" ]
-      defines += [ "TARGET_ABI_EABI" ]
     } else if (dart_target_arch == "arm64" || dart_target_arch == "simarm64") {
       defines += [ "TARGET_ARCH_ARM64" ]
     } else if (dart_target_arch == "mips" || dart_target_arch == "simmips") {
       defines += [ "TARGET_ARCH_MIPS" ]
     } 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")
+      print("Invalid dart_target_arch: $dart_target_arch")
       assert(false)
     }
   }
 
   if (dart_debug) {
     defines += [ "DEBUG" ]
   } else {
     defines += [ "NDEBUG" ]
   }
 
@@ skipping 147 matching lines @@
     "third_party/double-conversion/src:libdouble_conversion",
     "vm:libdart_lib",
     "vm:libdart_lib_nosnapshot",
     "vm:libdart_vm",
     "vm:libdart_vm_nosnapshot",
   ]
   sources = [
     "vm/libdart_dependency_helper.cc",
   ]
 }