On a x86_64 computer Nyxt fails to build because php fails to build.

`guix describe` outputs:

```
Generation 24   May 12 2021 18:06:24    (current)
  guix d6aeebb
    repository URL: https://git.savannah.gnu.org/git/guix.git
    branch: master
    commit: d6aeebb23639258311fdfb9dbf5f903079fde51a
```

When I run `guix build --no-substitutes nyxt` the build fails with this
error:

```
make: *** [Makefile:237: test] Error 1

Test suite failed, dumping logs.
command "make" "test" "-j" "8" failed with status 2
builder for `/gnu/store/a03k6dm154hg2q97pyi4xqiwwc7mn95v-php-7.4.19.drv' failed with exit code 1
build of /gnu/store/a03k6dm154hg2q97pyi4xqiwwc7mn95v-php-7.4.19.drv failed
View build log at '/var/log/guix/drvs/a0/3k6dm154hg2q97pyi4xqiwwc7mn95v-php-7.4.19.drv.bz2'.
cannot build derivation `/gnu/store/waxz9g4h7i19inc378j8si3wzz5jh9xj-libsoup-2.72.0.drv': 1 dependencies couldn't be built
building /gnu/store/8ipd965g9c4fpwf3x6ybwdcw2jjmlmd0-trivia-0.0.0-3.7286d5d-checkout.drv...
cannot build derivation `/gnu/store/r0kzlvzvh61585bd5k416rjp1mr3vkd0-nyxt-2-pre-release-7.drv': 1 dependencies couldn't be built
guix build: error: build of `/gnu/store/r0kzlvzvh61585bd5k416rjp1mr3vkd0-nyxt-2-pre-release-7.drv' failed
```

The build log is attached.