softfloat: Resolve type mismatches between declaration and implementation

softfloat: Resolve type mismatches between declaration and implementation

The original SoftFloat 2.0b library avoided the use of custom integer types
in its public headers. This requires the definitions of int{8,16,32,64} to
match the assumptions in the declarations. This breaks on BeOS R5 and Haiku/x86,
where int32 is defined in {be,os}/support/SupportDefs.h in terms of a long
rather than an int. Spotted by Michael Lotz.

Since QEMU already breaks this distinction by defining those types just above,
do use them for consistency and to allow #ifndef'ing them out as done for
[u]int16 on AIX.

Cc: Michael Lotz <mmlr@mlotz.ch>
Cc: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Andreas Färber <andreas.faerber@web.de>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>