XL: Add options to choose beween 64-bit and 32-bit builds
As discussed in !1644 (closed) CMake has no first-class way to specify 64-bit builds with XL tools. Currently it can only be done reliably by setting the OBJECT_MODE
environment variable. The compiler, linker, and archiver all have flags that CMake would need to add in the proper places (e.g. -q64
and -X 64
).