Bug#1086025: loupe: FTBFS with DEB_BUILD_OPTIONS=optimize=-lto: Unrecognized option: 'config'

[Simon McVittie]

Source: loupe
Version: 47.1-2
Severity: serious
Tags: ftbfs
Justification: fails to build from source (but built successfully in the past)
X-Debbugs-Cc: debian-rust at lists.debian.org

loupe failed to build (again) on the 32-bit release architectures armel,
armhf and i386:

https://buildd.debian.org/status/fetch.php?pkg=loupe&arch=armel&ver=47.1-2&stamp=1729795225&raw=0
> Running `CARGO=/usr/share/cargo/bin/cargo […] /<<PKGBUILDDIR>>/obj-arm-linux-gnueabi/src/armv5te-unknown-linux-gnueabi/release/deps/loupe-c4a9e232bbfbc423 --test-threads=1 --config profile.release.lto=false`
> error: Unrecognized option: 'config'

These are exactly the architectures where this package is built with
"optimize=-lto" in DEB_BUILD_OPTIONS, to work around previous versions
running out of virtual address space on 32-bit machines.

I don't know Rust, but this looks to me to be more like a problem with
how `cargo test` is invoking the test executable, rather than a problem
with this specific package.

loupe is almost a leaf package (gnome-core depends on it, but nothing
else does). If it is going to have recurring build problems on 32-bit,
perhaps instead of disabling LTO we should just not build it on the
32-bit architectures, and make gnome-core depend on loupe on 64-bit
architectures and eog on 32-bit?

    smcv