GN Build fixes for Flutter + gen_snapshot fix

runtime/platform/globals.h

 // Copyright (c) 2012, 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.
 
-#ifndef PLATFORM_GLOBALS_H_
-#define PLATFORM_GLOBALS_H_
+#ifndef RUNTIME_PLATFORM_GLOBALS_H_
+#define RUNTIME_PLATFORM_GLOBALS_H_
 
 // __STDC_FORMAT_MACROS has to be defined before including <inttypes.h> to
 // enable platform independent printf format specifiers.
 #ifndef __STDC_FORMAT_MACROS
 #define __STDC_FORMAT_MACROS
 #endif
 
 #if defined(_WIN32)
 // Cut down on the amount of stuff that gets included via windows.h.
 #if !defined(WIN32_LEAN_AND_MEAN)
@@ skipping 112 matching lines @@
 #else  // defined(PRODUCT)
 #define NOT_IN_PRODUCT(code) code
 #if defined(DEBUG)
 #define DEBUG_ONLY(code) code
 #else  // defined(DEBUG)
 #define DEBUG_ONLY(code)
 #endif  // defined(DEBUG)
 #endif  // defined(PRODUCT)
 
 
+#if defined(DART_PRECOMPILED_RUNTIME) && defined(DART_PRECOMPILER)
+#error DART_PRECOMPILED_RUNTIME and DART_PRECOMPILER are mutually exclusive
+#endif  // defined(DART_PRECOMPILED_RUNTIME) && defined(DART_PRECOMPILER)
+
 namespace dart {
 
 struct simd128_value_t {
   union {
     int32_t int_storage[4];
     float float_storage[4];
     double double_storage[2];
   };
   simd128_value_t& readFrom(const float* v) {
     float_storage[0] = v[0];
@@ skipping 518 matching lines @@
 // For checking deterministic graph generation, we can store instruction
 // tag in the ICData and check it when recreating the flow graph in
 // optimizing compiler. Enable it for other modes (product, release) if needed
 // for debugging.
 #if defined(DEBUG)
 #define TAG_IC_DATA
 #endif
 
 }  // namespace dart
 
-#endif  // PLATFORM_GLOBALS_H_
+#endif  // RUNTIME_PLATFORM_GLOBALS_H_