Target platform in build dir name deviates from actual target platform when building for 64bit Linux

To reproduce

1. Configure for 64 bit Linux:

   cd /location/of/viewer-dev-checkout/

   autobuild configure -c DebugOS -- -DWORD_SIZE=64

Expected

[...]

-- Build files have been written to: /location/of/viewer-dev-checkout/build-linux-x86_64

(See Compiling the viewer (Linux) > Where's the built viewer?)

Observed

[...]

-- Build files have been written to: /location/of/viewer-dev-checkout/build-linux-i686

Note

The location of the build dir is passed to CMake by autobuild, based on the platform it detects and the content of autobuild.xml in the viewer source. With -- -DWORD_SIZE=64, we only override the platform for CMake, not autobuild. As far as I know, we currently can't tell autobuild manually about the target platform.