gnu: Fix top-level circular references between emacs.scm and llvm.scm.

Previously, loading either of these two modules could fail somewhat
non-deterministically because each top-level was referencing a variable
defined by the other module's top-level.

* gnu/packages/emacs.scm (package-elisp-from-package): Move to...
* gnu/packages/llvm.scm (package-elisp-from-package): Here.  Keep
private.

1 files changed, 29 insertions, 0 deletions

diff --git a/gnu/packages/llvm.scm b/gnu/packages/llvm.scm
index 6dab9c5195..b1e41d72f9 100644
--- a/gnu/packages/llvm.scm
+++ b/gnu/packages/llvm.scm
@@ -479,6 +479,35 @@ code analysis tools.")
      "This package provides a Python binding to LLVM for use in Numba.")
     (license license:bsd-3)))
 
+(define (package-elisp-from-package source-package package-name
+                                    source-files)
+  "Return a package definition named PACKAGE-NAME that packages the Emacs Lisp
+SOURCE-FILES found in SOURCE-PACKAGE."
+  (let ((orig (package-source source-package)))
+    (package
+      (inherit source-package)
+      (name package-name)
+      (build-system emacs-build-system)
+      (source (origin
+                (method (origin-method orig))
+                (uri (origin-uri orig))
+                (sha256 (origin-sha256 orig))
+                (file-name (string-append package-name "-"
+                                          (package-version source-package)))
+                (modules '((guix build utils)
+                           (srfi srfi-1)
+                           (ice-9 ftw)))
+                (snippet
+                 `(let* ((source-files (quote ,source-files))
+                         (basenames (map basename source-files)))
+                    (map copy-file
+                         source-files basenames)
+                    (map delete-file-recursively
+                         (fold delete
+                               (scandir ".")
+                               (append '("." "..") basenames)))
+                    #t)))))))
+
 (define-public emacs-clang-format
   (package
     (inherit clang)