Add include of float.h for LDBL_MIN_EXP and LDBL_MANT_DIG

(cherry picked from commit 1711c6ea3a0d891da665325c75738a68bd7d501f)

Change-Id: Ia64676b2b904f042fec678003e3f2cd5bd82b510
diff --git a/tests/math_test.cpp b/tests/math_test.cpp
index 0bb072a..80083fa 100644
--- a/tests/math_test.cpp
+++ b/tests/math_test.cpp
@@ -51,6 +51,7 @@
 #include <gtest/gtest.h>
 
 #include <fenv.h>
+#include <float.h>
 #include <limits.h>
 #include <stdint.h>