Fix objasm 4 warnings. Enable (S|U)MULL/CLZ in math code.
Jeffrey Lee authored
Detail:
  s/longlong - The code has always had the ability to use CLZ & long multiply instructions, but it's never been enabled. The nonfunctional code to detect the CPU architecture at runtime has been disabled, and instead a fixed configuration is selected at compile time with the help of Hdr:CPU.Arch. Also added lots of ROUT's for safety.
  s/objmacs - Updated push/pop macros to make use of LDR/STR when only one register is to be transferred. This fixes a few objasm 4 warnings and should result in a speed boost where applicable.
Admin:
  Tested on rev A2 BB-xM.
  Different math code configurations tested briefly.


Version 5.61. Tagged as 'RISC_OSLib-5_61'
a6d65423