variable, float_exception_mask (#defined to _softfloat_float_exception_mask)
contains the current exception mask.
Also make the argument to float_raise into an fp_except.
Also synchronise file header comments between files.
but not in EGCS.
This version of fixunssfsi is almost exactly the arm32 version. fixunsdfsi is
mostly based on fixdfsi, but with simplifications for 64-bit integers.
Only minimal testing has been applied so far.