fix for MdaTransientPatch.hpp missing definition of exp10f

[gronkern]

Compilation gave me the error:

In file included from ./Source/factory.h:43:0,
                 from ./Source/FactoryPatches.cpp:35:
./Libraries/OwlPatches/mdaPorts/MdaTransientPatch.hpp: In member function 'void MdaTransientPatch::setParameters()':
./Libraries/OwlPatches/mdaPorts/MdaTransientPatch.hpp:68:44: error: 'exp10f' was not declared in this scope
  dry = (float)(exp10f((2.0 * fParam3) - 1.0));

for version 89f328af27 of the Patches. Fixed the compilation with a additional CPPFLAG for the math.h header included in gcc-arm-none-eabi-5_4-2016q3-20160926-linux.