Revert new OS and CC detection and related changes since r15923.

src/compiler-intrinsics.h

 // Copyright 2006-2008 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 10 matching lines @@
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #ifndef V8_COMPILER_INTRINSICS_H_
 #define V8_COMPILER_INTRINSICS_H_
 
-#include "globals.h"
-
 namespace v8 {
 namespace internal {
 
 class CompilerIntrinsics {
  public:
   // Returns number of zero bits preceding least significant 1 bit.
   // Undefined for zero value.
   INLINE(static int CountTrailingZeros(uint32_t value));
 
   // Returns number of zero bits following most significant 1 bit.
   // Undefined for zero value.
   INLINE(static int CountLeadingZeros(uint32_t value));
 
   // Returns the number of bits set.
   INLINE(static int CountSetBits(uint32_t value));
 };
 
-#if V8_CC_GNU
-
+#ifdef __GNUC__
 int CompilerIntrinsics::CountTrailingZeros(uint32_t value) {
   return __builtin_ctz(value);
 }
 
 int CompilerIntrinsics::CountLeadingZeros(uint32_t value) {
   return __builtin_clz(value);
 }
 
 int CompilerIntrinsics::CountSetBits(uint32_t value) {
   return __builtin_popcount(value);
 }
 
-#elif V8_CC_MSVC
+#elif defined(_MSC_VER)
 
 #pragma intrinsic(_BitScanForward)
 #pragma intrinsic(_BitScanReverse)
 
 int CompilerIntrinsics::CountTrailingZeros(uint32_t value) {
   unsigned long result;  //NOLINT
   _BitScanForward(&result, static_cast<long>(value));  //NOLINT
   return static_cast<int>(result);
 }
 
@@ skipping 13 matching lines @@
   return value;
 }
 
 #else
 #error Unsupported compiler
 #endif
 
 } }  // namespace v8::internal
 
 #endif  // V8_COMPILER_INTRINSICS_H_