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

runtime/vm/disassembler_arm.cc

 // Copyright (c) 2013, 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.
 
 #include "vm/disassembler.h"
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_ARM.
 #if defined(TARGET_ARCH_ARM)
 #include "platform/assert.h"
 #include "vm/cpu.h"
@@ skipping 94 matching lines @@
 // Print the condition guarding the instruction.
 void ARMDecoder::PrintCondition(Instr* instr) {
   Print(cond_names[instr->ConditionField()]);
 }
 
 
 // These register names are defined in a way to match the native disassembler
 // formatting, except for register alias pp (r5).
 // See for example the command "objdump -d <binary file>".
 static const char* reg_names[kNumberOfCpuRegisters] = {
-#if defined(TARGET_ABI_IOS)
+#if defined(TARGET_OS_MACOS) || TARGET_OS_IOS
     "r0", "r1", "r2",  "r3",  "r4", "pp", "r6", "fp",
     "r8", "r9", "thr", "r11", "ip", "sp", "lr", "pc",
-#elif defined(TARGET_ABI_EABI)
+#else
     "r0", "r1", "r2",  "r3", "r4", "pp", "r6", "r7",
     "r8", "r9", "thr", "fp", "ip", "sp", "lr", "pc",
-#else
-#error Unknown ABI
 #endif
 };
 
 
 // Print the register name according to the active name converter.
 void ARMDecoder::PrintRegister(int reg) {
   ASSERT(0 <= reg);
   ASSERT(reg < kNumberOfCpuRegisters);
   Print(reg_names[reg]);
 }
@@ skipping 1405 matching lines @@
       *object = NULL;
     }
   }
 }
 
 #endif  // !PRODUCT
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM