ImathMath std::hypot at android ndk r15b is not exist

`
jni/../../../../src/Imath/src/Imath/ImathMath.h:106:40: error: no member named 'hypot' in namespace
'std'; did you mean simply 'hypot'?
static T hypot (T x, T y) { return std::hypot (x, y); }
^~~~~~~~~~
hypot
jni/../../../../src/Imath/src/Imath/ImathMath.h:106:14: note: 'hypot' declared here
static T hypot (T x, T y) { return std::hypot (x, y); }
`
use c api is correct.
return hypot (x, y);

Start in jni/../../../../src/Imath/src/Imath/ImathMath.h at line 106, where ImathMath::hypot calls std::hypot. Build the Android target with Android NDK r15b and verify that the C API call works without the reported missing-member error.

Written by the indexing model from the issue text.