Make the Guix package use the current sources

* guix.scm: Use Guile-Git to find the list of source files, and use
those files for the source field of the package.

guix.scm

@@ -1,10 +1,12 @@
-(use-modules (gnu packages)
+(use-modules (git)
+             (gnu packages)
              (gnu packages autotools)
              (gnu packages code)
              (gnu packages guile)
              (gnu packages pkg-config)
              (guix build utils)
              (guix build-system gnu)
+             (guix gexp)
              ((guix licenses) #:prefix license:)
              (guix packages)
              (guix utils)
@@ -21,10 +23,21 @@
       (close-pipe pipe)
       version)))
 
+(define (make-select)
+  (let* ((directory (repository-discover "/home/samplet/code/geesh"))
+         (repository (repository-open directory))
+         (oid (reference-target (repository-head repository)))
+         (commit (commit-lookup repository oid))
+         (tree (commit-tree commit))
+         (paths (tree-list tree)))
+    (lambda (file stat)
+      (let ((relative (substring file (1+ (string-length *srcdir*)))))
+        (member relative paths)))))
+
 (package
   (name "geesh")
   (version *version*)
-  (source #f)
+  (source (local-file *srcdir* #:recursive? #t #:select? (make-select)))
   (build-system gnu-build-system)
   (native-inputs
    `(("autoconf" ,autoconf)