Support PowerPC64 architecture

[runlevel5]

Changes

• Support PowerPC64 Little Endian
• Support PowerPC64 Big Endian

[runlevel5]

To address the build error:

/home/tle/Work/ETe/src/qcommon/common.c:3622:13: error: redefinition of ‘Sys_GetProcessorId’
 3622 | static void Sys_GetProcessorId( char *vendor )
      |             ^~~~~~~~~~~~~~~~~~

[runlevel5]

POWER8 is the first to support Little Endian. This is the lowest common value for all CPUs that supports LE for example POWER8, POWER9 and POWER10

ref: https://www.ibm.com/docs/en/openxl-c-and-cpp-aix/17.1.0?topic=options-mcpu

[runlevel5]

Fallback to generic 64bit PPC64 if not LE

[ensiform]

I will consider it but keep in mind that there will be zero support on any 3rd party servers or existing mods that lack ppc/ppc64 support as ET does not use QVM like Q3A.

Also is there a reason you need to "force" with -mcpu? Shouldn't it be active if compiling on such target machine?

[runlevel5]

I will consider it but keep in mind that there will be zero support on any 3rd party servers or existing mods that lack ppc/ppc64 support as ET does not use QVM like Q3A.

Yes I am fully aware of that. This is mainly for PowerPC community to host their own LAN games

Also is there a reason you need to "force" with -mcpu? Shouldn't it be active if compiling on such target machine?

Well, if not specified, the value of mcpu would be determined with GCC configuration. However it's recommended to specify this parameter explicitly for many reasons, one of that is backward-compatibility, for example if compiling on a POWER9 machine, the -mcpu would be set to power9 which has instructions that are not compatible with POWER8 machine