guix pull on HEAD crashes

[Nils Gillmann]

On a commit from ~30 minutes ago, guix pull fails:

substitute: updating list of substitutes from 'https://berlin.guixsd.org'... 
100.0%
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'... 
100.0%
The following derivations will be built:
/gnu/store/7b8zpi91v86hna3sch8lpx45qzngnb38-guix-df1eaffc3.drv
/gnu/store/l4zws3m77kd2qbjdsa5dbfr5ppn2l37l-guix-packages-source.drv
/gnu/store/hcqb41mn0pi7ja8s3qp5a0sblcabgvis-guix-cli-source.drv
/gnu/store/g3m4p93faz5q1pbf07bfh8spl28kilx6-guix-system-source.drv
/gnu/store/5nkb58kwsa79c2ng1w6bvdfj5ajrcaqx-guix-extra-source.drv
/gnu/store/g85hsxn244c8yq0byichjjxnirkxj13p-config.scm.drv
/gnu/store/224ib07afla20xmbvj1ip7g8b45lh4gj-guix-config-source.drv
/gnu/store/0q5cg41piviwnw94fkywyiig2d1gswir-guix-packages.drv
/gnu/store/10dmanwa07x1w29rf1l0vjr7ds0g7zpg-guix-system.drv
/gnu/store/2fz3if302cqbb62pgqmwr1rwbaasgmwg-guix-extra.drv
/gnu/store/5wsx77qgalcxc1pkxldwqh69f10c543f-guix-cli.drv
/gnu/store/h830wc79b7s6awsgl9q3mhkhcy6fhcs0-guix-config.drv
loading...   94.3% of 106 filesrandom seed for tests: 1525020749
compiling... 100.0% of 106 files
compiling... 100.0% of 1 files
compiling... 100.0% of 407 files
Backtrace:
Exception thrown while printing backtrace:
In procedure private-lookup: No variable bound to define-module* in module 
(guile)

builder for `/gnu/store/0q5cg41piviwnw94fkywyiig2d1gswir-guix-packages.drv' 
failed with exit code 1
cannot build derivation 
`/gnu/store/7b8zpi91v86hna3sch8lpx45qzngnb38-guix-df1eaffc3.drv': 1 
dependencies couldn't be built
guix pull: error: build failed: build of 
`/gnu/store/7b8zpi91v86hna3sch8lpx45qzngnb38-guix-df1eaffc3.drv' failed