utils: Add helper for invoking programs.

* guix/build/utils.scm (invoke): New variable.

Co-authored-by: Ludovic Courtès <ludo@gnu.org>

guix/build/utils.scm

@@ -84,6 +84,7 @@
             fold-port-matches
             remove-store-references
             wrap-program
+            invoke
 
             locale-category->string))
 
@@ -579,6 +580,15 @@ Where every <*-phase-name> is an expression evaluating to a symbol, and
     ((_ phases (add-after old-phase-name new-phase-name new-phase))
      (alist-cons-after old-phase-name new-phase-name new-phase phases))))
 
+(define (invoke program . args)
+  "Invoke PROGRAM with the given ARGS.  Raise an error if the exit
+code is non-zero; otherwise return #t."
+  (let ((status (apply system* program args)))
+    (unless (zero? status)
+      (error (format #f "program ~s exited with non-zero code" program)
+             status))
+    #t))
+
 
 ;;;
 ;;; Text substitution (aka. sed).