Reinstate workarounds for atan2, fmod, pow in MathExtras on vs2013

Source/wtf/MathExtrasTest.cpp

 /*
  * Copyright (C) 2012 Intel Corporation
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 157 matching lines @@
     unsigned long long overflowUnsigned = maxUnsigned + 1;
 
     EXPECT_GT(overflowUnsigned, maxUnsigned);
 
     EXPECT_EQ(clampTo<unsigned>(maxUnsigned), maxUnsigned);
 
     EXPECT_EQ(clampTo<unsigned>(overflowUnsigned), maxUnsigned);
     EXPECT_EQ(clampTo<unsigned>(-1), 0u);
 }
 
+// Make sure that various +-inf cases are handled properly (they aren't
+// by default on VS).
+TEST(WTF, infinityMath)
+{
+    double posInf = std::numeric_limits<double>::infinity();
+    double negInf = -std::numeric_limits<double>::infinity();
+    double nan = std::numeric_limits<double>::quiet_NaN();
+
+    EXPECT_EQ(atan2(posInf, posInf), M_PI_4);
+    EXPECT_EQ(atan2(posInf, negInf), 3.0 * M_PI_4);
+    EXPECT_EQ(atan2(negInf, posInf), -M_PI_4);
+    EXPECT_EQ(atan2(negInf, negInf), -3.0 * M_PI_4);
+
+    EXPECT_EQ(fmod(0.0, posInf), 0.0);
+    EXPECT_EQ(fmod(7.0, posInf), 7.0);
+    EXPECT_EQ(fmod(-7.0, posInf), -7.0);
+    EXPECT_EQ(fmod(0.0, negInf), 0.0);
+    EXPECT_EQ(fmod(7.0, negInf), 7.0);
+    EXPECT_EQ(fmod(-7.0, negInf), -7.0);
+
+    EXPECT_EQ(pow(5.0, 0.0), 1.0);
+    EXPECT_EQ(pow(-5.0, 0.0), 1.0);
+    EXPECT_EQ(pow(nan, 0.0), 1.0);
+}
+
 } // namespace