Added missing #include.

Prevented macro substitution of fpclassify.

[SVN r45913]

libs/math

@@ -1 +1 @@
-Subproject commit 0d491f42a275a0e543ff88b170dea0170a7f0523
+Subproject commit 4a4271a5945de65545cd556fd7ec42f765fda9a4