ARM: Support hardfloat in SCons build and make it a build time setting

src/arm/macro-assembler-arm.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 837 matching lines @@
 
   // Print a message to stdout and abort execution.
   void Abort(const char* msg);
 
   // Verify restrictions about code generated in stubs.
   void set_generating_stub(bool value) { generating_stub_ = value; }
   bool generating_stub() { return generating_stub_; }
   void set_allow_stub_calls(bool value) { allow_stub_calls_ = value; }
   bool allow_stub_calls() { return allow_stub_calls_; }
 
+  // EABI variant for double arguments in use.
+  bool use_eabi_hardfloat() {
+#if USE_EABI_HARDFLOAT
+    return true;
+#else
+    return false;
+#endif
+  }
+
   // ---------------------------------------------------------------------------
   // Number utilities
 
   // Check whether the value of reg is a power of two and not zero. If not
   // control continues at the label not_power_of_two. If reg is a power of two
   // the register scratch contains the value of (reg - 1) when control falls
   // through.
   void JumpIfNotPowerOfTwoOrZero(Register reg,
                                  Register scratch,
                                  Label* not_power_of_two_or_zero);
@@ skipping 229 matching lines @@
 #define __FILE_LINE__ __FILE__ ":" CODE_COVERAGE_TOSTRING(__LINE__)
 #define ACCESS_MASM(masm) masm->stop(__FILE_LINE__); masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_MACRO_ASSEMBLER_ARM_H_