[Bug-apl] Does not build on powerpc platforms (or anything with ldbl range == dbl range)

[Daniel Kolesa]

Since after 1.7 the src/Tokenizer.cc code has been changed to use precomputed 
tables for exponent, but now the compilation fails with

Tokenizer.cc:769:4: error: floating constant exceeds range of 'long double' 
[-Werror=overflow]
    exp_0_9(1E30)

This is because on powerpc, depending on libc, long double is either "quad 
precision" double-double format (which has the same range as an ordinary 
double, just higher precision) or simply the same type as a regular double. 
Reverting to the older code fixes the problem.

- q66