Revert "ci: Build Guix System images."

This reverts commit eda3fcfb46586710fff876ce6254b300795ef543.

This change broke evaluations on CI:

  @ build-succeeded /gnu/store/991738x97ff1f8181a7p1pflqwkgagm8-profile.drv -
  ERROR: In procedure read:
  In procedure scm_lreadr: #<unknown port>:16:144: Unknown # object: #\<

1 files changed, 35 insertions, 39 deletions

diff --git a/gnu/ci.scm b/gnu/ci.scm
index 3ff43522d4..fa67168e22 100644
--- a/gnu/ci.scm
+++ b/gnu/ci.scm
@@ -53,7 +53,6 @@
   #:use-module (gnu system image)
   #:use-module (gnu system vm)
   #:use-module (gnu system install)
-  #:use-module (gnu system images hurd)
   #:use-module (gnu tests)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-26)
@@ -186,21 +185,18 @@ SYSTEM."
               (remove (either from-32-to-64? same? pointless?)
                       %cross-targets)))
 
-;; Architectures that are able to build or cross-build Guix System images.
-;; This does not mean that other architectures are not supported, only that
-;; they are often not fast enough to support Guix System images building.
-(define %guix-system-supported-systems
-  '("x86_64-linux" "i686-linux"))
+(define %guixsd-supported-systems
+  '("x86_64-linux" "i686-linux" "armhf-linux"))
 
-(define %guix-system-images
-  (list hurd-barebones-disk-image))
+(define %u-boot-systems
+  '("armhf-linux"))
 
-(define (image-jobs store system)
-  "Return a list of jobs that build images for SYSTEM."
+(define (qemu-jobs store system)
+  "Return a list of jobs that build QEMU images for SYSTEM."
   (define (->alist drv)
     `((derivation . ,(derivation-file-name drv))
-      (description . "Stand-alone image of the GNU system")
-      (long-description . "This is a demo stand-alone image of the GNU
+      (description . "Stand-alone QEMU image of the GNU system")
+      (long-description . "This is a demo stand-alone QEMU image of the GNU
 system.")
       (license . ,(license-name gpl3+))
       (max-silent-time . 600)
@@ -215,34 +211,30 @@ system.")
                    (parameterize ((%graft? #f))
                      (->alist drv))))))
 
-  (define (build-image image)
-    (run-with-store store
-      (mbegin %store-monad
-        (set-guile-for-build (default-guile))
-        (lower-object (system-image image)))))
-
   (define MiB
     (expt 2 20))
 
-  (if (member system %guix-system-supported-systems)
-      `(,(->job 'usb-image
-                (build-image
-                 (image
-                  (inherit efi-disk-image)
-                  (size (* 1500 MiB))
-                  (operating-system installation-os))))
-        ,(->job 'iso9660-image
-                (build-image
-                 (image
-                  (inherit iso9660-image)
-                  (operating-system installation-os))))
-        ;; Only cross-compile Guix System images from x86_64-linux for now.
-        ,@(if (string=? system "x86_64-linux")
-              (map (lambda (image)
-                     (->job (image-name image) (build-image image)))
-                   %guix-system-images)
-              '())
-        '())))
+  (if (member system %guixsd-supported-systems)
+      (list (->job 'usb-image
+                   (run-with-store store
+                     (mbegin %store-monad
+                       (set-guile-for-build (default-guile))
+                       (lower-object
+                        (system-image
+                         (image
+                          (inherit efi-disk-image)
+                          (size (* 1500 MiB))
+                          (operating-system installation-os)))))))
+            (->job 'iso9660-image
+                   (run-with-store store
+                     (mbegin %store-monad
+                       (set-guile-for-build (default-guile))
+                       (lower-object
+                        (system-image
+                         (image
+                          (inherit iso9660-image)
+                          (operating-system installation-os))))))))
+      '()))
 
 (define channel-build-system
   ;; Build system used to "convert" a channel instance to a package.
@@ -313,7 +305,11 @@ system.")
                                 "." system))))
       (cons name (test->thunk test))))
 
-  (if (member system %guix-system-supported-systems)
+  (if (and (member system %guixsd-supported-systems)
+
+           ;; XXX: Our build farm has too few ARMv7 machines and they are very
+           ;; slow, so skip system tests there.
+           (not (string=? system "armhf-linux")))
       ;; Override the value of 'current-guix' used by system tests.  Using a
       ;; channel instance makes tests that rely on 'current-guix' less
       ;; expensive.  It also makes sure we get a valid Guix package when this
@@ -490,7 +486,7 @@ Return #f if no such checkout is found."
                                   (package->job store package
                                                 system))))
                        (append (filter-map job all)
-                               (image-jobs store system)
+                               (qemu-jobs store system)
                                (system-test-jobs store system
                                                  #:source source
                                                  #:commit commit)