By having no problem I mean we know enough about writing an optimizer to write such a thing. I don't think any compiler does, just that they could.
Most people wrote assembler particularly if they wanted to use more then 64k.
Most non assembly programs were interpreted oddly enough and most such interpreters were also mostly 64k.
Turbo Pascal 3.x always had a single code segment, a single data segment, a single stack segment + a heap. Heap allocations were paragraph aligned (ofs=0). All pointers were far pointers.
Turbo Pascal 4.0 and up had one code segment per module (that they called units). It still had a single data segment and a single stack segment + a heap. Heap allocations were still paragraph aligned and all pointers were still far pointers.
Turbo/Borland Pascal 7.0 also supported 16-bit protected mode. I don't know if heap allocations had ofs=0 there.
None of them had "huge" arrays/pointers where pointers can point to things bigger than 64K -- at the cost of a lot of instructions for pointer arithmetic and array indexing.