Require CMOV support for the ia32 port.

src/platform-posix.cc

Index: src/platform-posix.cc
diff --git a/src/platform-posix.cc b/src/platform-posix.cc
index 1fb6da75ccf636ed63b01f7ced8bea5ff6278d7d..1370dedcf8f3abb1db8784a156744ce506dfdbab 100644
--- a/src/platform-posix.cc
+++ b/src/platform-posix.cc
@@ -54,14 +54,7 @@ static const pthread_t kNoThread = (pthread_t) 0;
 
 
 uint64_t OS::CpuFeaturesImpliedByPlatform() {
-#if V8_OS_MACOSX
-  // Mac OS X requires CMOV to install so we can assume it is present.
-  // These constants are defined by the CPUid instructions.
-  const uint64_t one = 1;
-  return one << CMOV;
-#else
-  return 0;  // Nothing special about the other systems.
-#endif
+  return 0;  // Nothing special.
 }