[Libunwind-devel] [PATCH v2 0/11] Fixup the PowerPC (64 & 32 bit) builds & clean up configure

[Cody P Schafer]

Build failures occured primarily due to
 - attempts to build the 32bit powerpc code as 64bit and vise versa.
   - solved by changing how configure checks for a 64bit compilation
 - libunwind-coredump lacking ppc support.
   - solved by making coredump an optional component and disabling it on 
everything but x86*.

Since v1:
 - removed empty lines
 - fixed libunwind-coredump build not building by default on x86*
 - replace AC_HELP_STRING with AS_HELP_STRING
 - factor out common AC_ARG_ENABLE useage into AX_ARG_ENABLE
 - Add ptrace register offsets for ppc64 & ppc32

Still not quite right:
 - test-ptrace emits quite a few errors on ppc64, I don't think
   libunwind-ptrace currently works on ppc64. Error at end of email for those
   interested.

Note: I reverted 8203c955c8bde94bba609d20abb39c576acf3e38 to build these
changes on top of the current tree.

`tests/test-ptrace` on ppc64:
----
 >_Uppc64_init_remote: (cursor=0xfffefcb6f10)
                >_UPT_access_reg: ???[114] -> 0
 >_UPT_access_reg: bad register number 1 (error: Input/output error)
unw_init_remote() failed: ret=-3
            >_UPT_get_dyn_info_list_addr: looking for dyn_info list
unw_get_proc_info(ip=0x0) failed: ret=-8
 >_Uppc64_step: (cursor=0xfffefcb6f10, ip=0x0000000000000000)
 >_Uppc64_init_remote: (cursor=0xfffefcb6f10)
                >_UPT_access_reg: ???[114] -> 4
 >_UPT_access_reg: bad register number 1 (error: Input/output error)
unw_init_remote() failed: ret=-3
            >_UPT_get_dyn_info_list_addr: looking for dyn_info list
unw_get_proc_info(ip=0x4) failed: ret=-8
 >_Uppc64_step: (cursor=0xfffefcb6f10, ip=0x0000000000000004)
            >_UPT_get_dyn_info_list_addr: looking for dyn_info list
               >_Uppc64_dwarf_step: returning -10
  >_Uppc64_step: Unable to retrieve CFA from back chain in stack frame - -8
FAILURE: unw_step() returned -8 for ip=4 (start ip=4)
[... the above (or similar errors) are repeated many times, then finally ...]
Too many errors (103)!
unwind failed with ret=-8
FAILURE: detected 105 errors
----