cargo-build-system: Accept a #:features argument

* guix/build/cargo-build-system.scm (build, install): Pass the features
  to cargo.
  (check): Remove indirection layer for consistency with build and
  install.
* guix/build-system/cargo.scm (cargo-build): New argument; pass it into
  the builder.
* gnu/packages/rust-apps.scm (ripgrep): Use the new argument instead of
  a custom phase.

gnu/packages/rust-apps.scm

@@ -244,18 +244,8 @@ provides defaults for 80% of the use cases.")
                 (install-file manpage (string-append
                                         (assoc-ref outputs "out")
                                         "/share/man/man1"))))
-             #t))
+             #t)))
-         (replace 'install
+       #:features '("pcre2")))
-           ;; Adapted from (guix build cargo-build-system). The flags need to
-           ;; be passed to `cargo install' too, as otherwise it will build
-           ;; another binary, without the features.
-           (lambda* (#:key outputs #:allow-other-keys)
-             (let ((out (assoc-ref outputs "out")))
-               (mkdir-p out)
-               (setenv "CARGO_TARGET_DIR" "./target")
-               (invoke "cargo" "install" "--path" "." "--root" out
-                       "--features" "pcre2")))))
-       #:cargo-build-flags '("--release" "--features" "pcre2")))
     (native-inputs
      `(("asciidoc" ,asciidoc)
        ("pcre2" ,pcre2)

guix/build-system/cargo.scm

@@ -4,6 +4,7 @@
 ;;; Copyright © 2013 Nikita Karetnikov <nikita@karetnikov.org>
 ;;; Copyright © 2016 David Craven <david@craven.ch>
 ;;; Copyright © 2019 Ivan Petkov <ivanppetkov@gmail.com>
+;;; Copyright © 2020 Jakub Kądziołka <kuba@kadziolka.net>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -76,6 +77,7 @@ to NAME and VERSION."
                       (vendor-dir "guix-vendor")
                       (cargo-build-flags ''("--release"))
                       (cargo-test-flags ''("--release"))
+                      (features ''())
                       (skip-build? #f)
                       (phases '(@ (guix build cargo-build-system)
                                   %standard-phases))
@@ -104,6 +106,7 @@ to NAME and VERSION."
                     #:vendor-dir ,vendor-dir
                     #:cargo-build-flags ,cargo-build-flags
                     #:cargo-test-flags ,cargo-test-flags
+                    #:features ,features
                     #:skip-build? ,skip-build?
                     #:tests? ,(and tests? (not skip-build?))
                     #:phases ,phases

guix/build/cargo-build-system.scm

@@ -3,6 +3,7 @@
 ;;; Copyright © 2017 Mathieu Othacehe <m.othacehe@gmail.com>
 ;;; Copyright © 2019 Ivan Petkov <ivanppetkov@gmail.com>
 ;;; Copyright © 2019, 2020 Efraim Flashner <efraim@flashner.co.il>
+;;; Copyright © 2020 Jakub Kądziołka <kuba@kadziolka.net>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -140,11 +141,14 @@ directory = '" port)
 
 (define* (build #:key
                 skip-build?
+                features
                 (cargo-build-flags '("--release"))
                 #:allow-other-keys)
   "Build a given Cargo package."
   (or skip-build?
-      (apply invoke `("cargo" "build" ,@cargo-build-flags))))
+      (apply invoke "cargo" "build"
+             "--features" (string-join features)
+             cargo-build-flags)))
 
 (define* (check #:key
                 tests?
@@ -152,10 +156,10 @@ directory = '" port)
                 #:allow-other-keys)
   "Run tests for a given Cargo package."
   (if tests?
-      (apply invoke `("cargo" "test" ,@cargo-test-flags))
+      (apply invoke "cargo" "test" cargo-test-flags)
       #t))
 
-(define* (install #:key inputs outputs skip-build? #:allow-other-keys)
+(define* (install #:key inputs outputs skip-build? features #:allow-other-keys)
   "Install a given Cargo package."
   (let* ((out (assoc-ref outputs "out")))
     (mkdir-p out)
@@ -168,7 +172,8 @@ directory = '" port)
     ;; otherwise cargo will raise an error.
     (or skip-build?
         (not (has-executable-target?))
-        (invoke "cargo" "install" "--path" "." "--root" out))))
+        (invoke "cargo" "install" "--path" "." "--root" out
+                "--features" (string-join features)))))
 
 (define %standard-phases
   (modify-phases gnu:%standard-phases