target/8569: gcc on alpha does not support global variables in shared objects

[Glen Nakamura]

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=8569

I remember running into this "gp-relative relocation" problem before...
Compiling with "-mno-explicit-relocs" seemed to get things working, so
I didn't investigate any further.  Hopefully, someone with a better
understanding can provide you with a proper solution.

- glen