Compaq/Digital Unix compilation issue

With postgres 6.5.2 if noticed a dependency on __alpha__ being required
for Digital Unix/Compaq Tru64 UNIX.

The cc compiler only sets __alpha.
I found that adding -D__alpha__ to the alpha_cc template seemed to fix
the compile problems.

With 6.5.1, only __alpha was used by the #ifdefs (which is correct)

found in:
backend/utils/adt/float.c
include/storage/s_lock.h:

Personally, I thing __alpha__ should be changed back to __alpha__, but
adding -D__alpha__ to the alpha__cc template works.

Tested on Compaq Tru64 v4.0d using cc.

regards,
    Dave Hill

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|Dave Hill                (0 0)    Unix Software Group     |
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