Irix4     : Version for Irix4 (COFF), compiled with SGI C++
Iris4-gcc : same as iris4 but compiled with g++
Irix5.2   : Version for Irix5.2 (Elf), compiled with SGI C++
Irix6.2   : Compiled using SGI C++ under Irix6.2 (Elf)

The GCC version is usually faster on scalar ops and slower
on vector ops, as compared to SGI C++ versions.

On Irix5.2, all three binaries should work, but only iris5
version supports dynamic linking. On Irix4.xx, the iris5
version cannot be used.

The Irix6.2 directory contains two binaries: one for "old 32-bit"
application binary interface (SGI_ABI = -32) and the other one
for 64-bit interface (SGI_ABI = -64).