Prevent compilation crash on OpenBSD when using FPC fixes.

FPC fixes can only be compiled/assembled with the old binutils (v2.17). The file generics.hashes.pas has a define for this.

https://gitlab.com/freepascal.org/fpc/source/-/blob/main/packages/rtl-generics/src/generics.hashes.pas?ref_type=heads#L65

However, when targeting x86_64, this define is not used. Correct code:

{$ifdef CPUX64}
{$ifndef DISABLE_X86_CPUINTEL}
{$define CPUINTEL}
{$ASMMODE INTEL}
{$endif}
{$endif}

This problem only surfaces when compiling on a real OpenBSD system. When cross-compiling towards OpenBSD, this problem remains undetected.

This fix might also be applied to trunk, if deemed necessary.