Incorporated _swi/_swix bug fix that was released in the RISC OS 3.70/3.71
Kevin Bracey authored
ROM patches.
fp and lr are now set correctly before calling a SWI. This allows much better
recovery if the SWI aborts or generates an error.

Version 4.95. Tagged as 'RISC_OSLib-4_95'
0c27e5e4