Bug#905345: sbuild should default to build profiles cross and nocheck for cross compilation

[Helmut Grohne <helmut@subdivi.de>]

Package: sbuild
Version: 0.77.0-4
Severity: wishlist

During the DebConf18 cross bof it was mentioned that cross building with
sbuild is still difficult, because you need to remember so many options.
sbuild already defaults to adding nocheck to DEB_BUILD_OPTIONS when it
detects a cross build. It is often necessary to use the build profiles
cross and/or nocheck to perform a successful cross build. Thus I perform
all of my cross builds with --profiles nocheck,cross. pbuilder also
defaults to adding nocheck to the build profiles and allows disabling
this with the --no-auto-cross flag.

I propose that sbuild defaults to the profiles cross and nocheck
whenever it detects cross compilation. To make this easy to override, I
propose that whenver the environment variable DEB_BUILD_PROFILES or the
--profiles flag is given (empty or not), this default is not applied.

What do you think?

Helmut