Reintroduce duplicate identifier detection in preparser.

src/win32-math.h

Index: src/win32-math.h
diff --git a/src/win32-math.h b/src/win32-math.h
new file mode 100644
index 0000000000000000000000000000000000000000..68759990b4307b5f40f0b528afbddfe5cea6c43b
--- /dev/null
+++ b/src/win32-math.h
@@ -0,0 +1,61 @@
+// 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
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// 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.
+
+// Extra POSIX/ANSI routines for Win32 when using Visual Studio C++. Please
+// refer to The Open Group Base Specification for specification of the correct
+// semantics for these functions.
+// (http://www.opengroup.org/onlinepubs/000095399/)
+
+#ifndef V8_WIN32_MATH_H_
+#define V8_WIN32_MATH_H_
+
+#ifndef _MSC_VER
+#error Wrong environment, expected MSVC.
+#endif  // _MSC_VER
+
+enum {
+  FP_NAN,
+  FP_INFINITE,
+  FP_ZERO,
+  FP_SUBNORMAL,
+  FP_NORMAL
+};
+
+namespace v8 {
+
+int isfinite(double x);
+
+}  // namespace v8
+
+int isnan(double x);
+int isinf(double x);
+int isless(double x, double y);
+int isgreater(double x, double y);
+int fpclassify(double x);
+int signbit(double x);
+
+#endif  // V8_WIN32_MATH_H_