[RFA] PPC ABI compliance fix

[Elena Zannoni]

Elena Zannoni writes:
 > 
 > Back in November, gcc changed the way structures <= 8 bytes are
 > returned on the PPC. The change was made to be compliant with the
 > SVR4 ABI.
 > 
 > http://gcc.gnu.org/ml/gcc-patches/2001-11/msg01468.html
 > 
 > The abi specifies that such structures are passed in r3 and r4.
 > Bigger structures are passed in memory.
 > 
 > Gcc was passing every structure in memory.  The change was made for
 > embedded targets, but not for natives (PowerPC Linux, NetBSD, and
 > FreeBSD).
 > 
 > Of course this change breaks binary compatibility with older gcc's.
 > Not sure what to do about that, if anything, the case it covers is a
 > corner case, anyway.
 > 
 > 
 > Elena
 > 
 > 
 > 2002-03-21  Elena Zannoni  <ezannoni@redhat.com>
 > 
 >         * ppc-linux-tdep.c (ppc_sysv_abi_use_struct_convention): New
 >         function.  
 > 	* ppc-tdep.h (ppc_sysv_abi_use_struct_convention): Export.
 >         * rs6000-tdep.c (rs6000_gdbarch_init): Use different
 >         structure returning convention for SYSV ABI case, but not
 >         for GNU/Linux, FreeBSD, or NetBSD.
 > 


Committed.

Elena