* Add all softfloat source files without any change.
* Remove useless file softfloat.mk.in, since gem5 use Scons.
* Add `use_fast_int64` in SConscript to distinguish src of two strategies for data
larger than 64 bits.
* The SoftFloat library uses two strategies to handle data larger than 64bit. One is
spliting data into `fast_int64`, and the other is using pointer. Two strategies
are distinguished by macro `SOFTFLOAT_FAST_INT64`. But not all "*.c" files are
guarded by this macro, which leads to including useless files in compiling progress
and compiling error. `use_fast_int64` used in SConscript can exclude unnecessary
files.
Change-Id: I7cec10412c00a35c247299cd92d83cdee9066410
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/66552
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Hoa Nguyen <hoanguyen@ucdavis.edu>