Solaris x86, 32 and 64 bit

[Hans Werner Strube]

So far, the Makefiles and prototype{,32,64} of pfil and ipf for Solaris
(64 bit) distinguish sparcv7 and sparcv9. However, in Solaris 10_x86 with AMD
64 bit support, the corresponding terms should be i86 and amd64, respectively.