More real.c fall out on m68k-elf toolchain.

[Graham Stott]

Richard,

I can no longer build a x86-x-m68k-elf toolchain due to an abort in real.c building newlib/libm/math/e_acos.c

/usr/local/src/uberbaum/newlib/libm/math/e_acos.c: In function `__ieee754_acos':
/usr/local/src/uberbaum/newlib/libm/math/e_acos.c:109: internal compiler error: in ten_to_ptwo, at real.c:2052

The abort occurs because ten_to_ptwo is called with invalid arg value 32 which is >= MAX_EXP.

Here's a reduced testcase compile which fails at -O1 or higher on m68k-elf toolchain.

---------------------------
static const double qS2 = 2.02094576023350569471e+00;

double foo(double x)
{
   return qS2;
}
----------------------------