#23 Building with GCC-6 Fails

[Hodorgasm]

Buiding pixie-2.2.6 with GCC-6 fails with errors such as:

In file included from ../common/algebra.h:188:0,
                 from file_tiff.h:33,
                 from file_tiff.cpp:32:
../common/mathSpec.h: In function ‘void fresnel(const float*, const float*, float, float&, float&, float*, float*)’:
../common/mathSpec.h:548:37: error: ‘max’ was not declared in this scope
  const SCALAR_TYPE g  = SQRT(max(t,0));
                                     ^
../common/mathSpec.h:553:17: error: ‘min’ was not declared in this scope
  Kr   = min(Kr,1);
                 ^

min and max are defined as real functions in GCC-6 and any code relying on their definition as macros may fail.

[Hodorgasm]

Actually, the other patch doesn't work if building with GCC-6 and including -std=c++98 in CXXFLAGS.