Hello, it looks as if commit ff5f34ae757d709987896d6164bf125319a0f764 breaks building of at least one package, perl-gd, depending on perl-extutils-pkgconfig.
The latter is now defined as (define-syntax perl-extutils-pkgconfig (identifier-syntax (perl-extutils-pkgconfig-for-target (%current-target-system)))) which apparently does not play well with what is written in the former as (native-inputs (list perl-extutils-pkgconfig)) : guix package: error: gnu/packages/gd.scm:103:2: package `perl-gd@2.73' has an invalid input: ("_" #<syntax-transformer perl-extutils-pkgconfig>) I do not quite see where the problem lies, given that the same thing has been working for pkg-config for quite a while now... I noticed it on core-updates, but the commit comes from master. Andreas