* SPARC: completely rewrote PIC-related code, got it twice shorter in source lines and much less instructions in generated code.
+ Enable registers %i0..%i5 and %o7 for use by reg.allocator.

Some notable properties of this implementation are:
  o pi_needs_got flag can be safely set during pass 2, so not setting it occasionally in pass 1 does not result in internal error.
  o Reg.allocator configuration is independent from PIC. If procedure requires GOT, register %l7 is allocated at the prologue, making it unavailable to RA.
  o GOT is stored in fixed %l7 register, but it is trivial to switch over to virtual register.


git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@26293 3ad0048d-3df7-0310-abae-a5850022a9f2