Compilation warning

[DamienCassou]

Hi,

when compiling files in this project, I get the following warning:

In toplevel form:
lib/nix-emacs/nixos-packages.el:28:43:Warning: reference to free variable
    ‘spacemacs-cache-directory’
lib/nix-emacs/nixos-packages.el:34:7:Warning: assignment to free variable
    ‘nixos-packages’
lib/nix-emacs/nixos-packages.el:46:1:Warning: value returned from (assoc
    "name" (car nixos-packages)) is unused
lib/nix-emacs/nixos-packages.el:46:20:Warning: reference to free variable
    ‘nixos-packages’
lib/nix-emacs/nixos-packages.el:47:1:Warning: value returned from (assoc
    "system" (car nixos-packages)) is unused
lib/nix-emacs/nixos-packages.el:48:1:Warning: value returned from (assoc
    "description" (assoc "meta" (car nixos-packages))) is unused
lib/nix-emacs/nixos-packages.el:49:1:Warning: value returned from (assoc
    "homepage" (assoc "meta" (car nixos-packages))) is unused
lib/nix-emacs/nixos-packages.el:50:1:Warning: value returned from (assoc
    "license" (assoc "meta" (car nixos-packages))) is unused
lib/nix-emacs/nixos-packages.el:51:1:Warning: value returned from (assoc
    "longDescription" (assoc "meta" (car nixos-packages))) is unused
lib/nix-emacs/nixos-packages.el:52:1:Warning: value returned from (assoc
    "platforms" (assoc "meta" (car nixos-packages))) is unused
lib/nix-emacs/nixos-packages.el:53:1:Warning: value returned from (assoc
    "position" (assoc "meta" (car nixos-packages))) is unused
lib/nix-emacs/nixos-packages.el:54:1:Warning: value returned from (assoc
    "maintainers" (assoc "meta" (car nixos-packages))) is unused
lib/nix-emacs/nixos-packages.el:55:1:Warning: value returned from (assoc
    "maintainers" (assoc "meta" (car nixos-packages))) is unused

In end of data:
lib/nix-emacs/nixos-packages.el:116:1:Warning: the following functions are not
    known to be defined: nixos-packages-get-description,
    nixos-packages-get-homepage, nixos-packages-get-license,
    nixos-packages-get-longDescription, nixos-packages-get-platforms,
    nixos-packages-get-maintainers, nixos-packages-get-position,
    nixos-packages-get-name, nixos-packages-get-system
Done (Total of 5 files compiled)