Omni OpenMP Compiler 64 bit environment status

Platforms

Omni 1.2 (and later) supports 64 bit machines, and this release contains 64 bit environment support. Developping and tested on:

On Alpha/Linux, you just follow Installation Notes to install 64 bit Omni compilers. If you want to use the Compaq C compiler as default backend, use --with-cc option with "configure" command. like:
```
configure --with-cc=ccc --with-opt='-O6 -arch ev67' ...
```
With the Compaq C compiler, you will encount many warnings in Omni compilation phase, but just ignore.
On IRIX, you have to compile with '-64' C compiler option. Use --with-opt option with "configure" command. like:
```
configure --with-cc=cc --with-opt='-64' ...
```

C issues:
- When writing this, there is no "known problems" for Omni C compiler. Not fully tested yet.
Fortran 77 issues:
- (including INTEGER*8 on 32 bit environment), INTEGER*8 is only available when backend C compiler has a integer type that size is 64 bit. Of cource the platforms above clears this.
- On Omni Fortran 77 compiler, default size of INTEGER is ALWAYS 4 bytes even if on 64 bit environment. If need changing it to 8 bytes, specify "-i8" option for omf77.
- When specifying "-i8" option with omf77, all integer constants will be treat as INTEGER*8 type.
- Implied DO in DATA statement will be computed as INTEGER*4 even if the DO variable (and statr/end/increment value) is INTEGER*8. Practically, I think no need to treat it as 64 bit. Am I wrong?
- Power expressions with INTEGER*8 are currently shrunken to INTEGER*4. Return value also.
- If the process addressing model is 64 bit, pointer variable of cray pointer extension must be INTEGER*8. And return value of LOC() is INTEGER*8. So do lock variables for OMP_*_LOCK(), but not tested yet.

For better perfomance on Linux/Alpha, the Compaq C compiler is preferred as a backend. It will be several times faster than gcc. Note that the Compaq C compiler can't handle long input line. Thus, It might fail to complie fortran souece that have large initilize block with DATA statement. Will be fixed in next Omni release.