Add <cmath> standard C++ header.

This is needed for upcoming STLport experimentation.

libstdc++/include/cmath

@@ -0,0 +1,71 @@
+/* -*- c++ -*- */
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ * 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.
+ *
+ * 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.
+ */
+
+#ifndef BIONIC_LIBSTDCPP_INCLUDE_CMATH__
+#define BIONIC_LIBSTDCPP_INCLUDE_CMATH__
+
+/*
+ * Standard C++ Library wrapper around the C time.h header file.
+ */
+
+#include <cstddef>
+#include <math.h>
+
+namespace std
+{
+// Functions.
+using ::cos;
+using ::sin;
+using ::tan;
+using ::acos;
+using ::asin;
+using ::atan;
+using ::atan2;
+
+using ::cosh;
+using ::sinh;
+using ::tanh;
+
+using ::exp;
+using ::frexp;
+using ::ldexp;
+using ::log;
+using ::log10;
+using ::modf;
+
+using ::pow;
+using ::sqrt;
+
+using ::ceil;
+using ::fabs;
+using ::floor;
+using ::fmod;
+}  // namespace std
+
+#endif  // BIONIC_LIBSTDCPP_INCLUDE_CMATH__