Old Android Phone "cannot locate 'log2'" Problem

I am upgraded My Project to 4.16.
Serious Problem happened.
It does build OK.
but during runtime,

07-07 11:18:08.273: E/AndroidRuntime(12717): Caused by: java.lang.UnsatisfiedLinkError: Cannot load library: reloc_library[1307]: 1847 cannot locate ‘log2’…
07-07 11:18:08.273: E/AndroidRuntime(12717): at java.lang.Runtime.loadLibrary(Runtime.java:370)

I can see this error.

It is because of Engine’s new code.

In VolumetricFog.cpp

FVector GetVolumetricFogGridZParams(float NearPlane, float FarPlane, int32 GridSizeZ)

float NearPlaneSlice = log2(NearPlane*FloatB + FloatO) * FloatS;


log2() function is the problem.
It is not compatible with old phone(SHW-M250S).

This must be fixed.
log2() can be changed to new defined macro.

please fix this problem.

Can I know if you’ve found any solution for this?