Architecture-specific settings for snapcraft parts

[Joseph Rushton Wakeling]

Hello all,

Recently I tried some ARM builds of the LDC snap package, and came across some 
issues where one of the custom C flags used were not supported:
https://launchpadlibrarian.net/313662608/buildlog_snap_ubuntu_xenial_armhf_ldc2_BUILDING.txt.gz

Is there any way to customize the settings for parts according to architecture? 
In this case I'm looking to customize the cmake configflags.

I could imagine maybe using a scriptlet to export some environment variable 
conditional on the architecture, but wondered if anyone else has any ideas.

Thanks & best wishes,

     -- Joe