But I am ashamed! :)
1. xfce4-cpugraph-plugin.scm
(use-modules (ice-9 match)
(srfi srfi-1)
(guix gexp)
(guix packages)
(guix build)
(guix licenses)
(guix git-download)
(define-public xfce4-cpugraph-plugin
(package
(name "xfce4-cpugraph-plugin")
(version "1.0.5")
(source (origin
(method url-fetch)
(uri (string-append
"http://archive.xfce.org/src/panel-plugins/"
name "/" (version-major+minor
version) "/"
name "-" version ".tar.bz2"))
(sha256
(base32
"1izl53q95m5xm2fiq7385vb1i9nwgjizxkmgpgh33zdckb40xnl5"))))
(build-system gnu-build-system)
(native-inputs `(("pkg-config" ,pkg-config)
("intltool" ,intltool)))
(inputs `(("glib" ,glib)
("gtk+" ,gtk+-2)
("libxfce4util" ,libxfce4util)
("libxfce4ui" ,libxfce4ui)
("xfce4-panel" ,xfce4-panel)))
(home-page
"https://goodies.xfce.org/projects/panel-plugins/")
(synopsis "cpugraph")
(description
"TEST")
(license (list gpl2+ lgpl2.0+))))
)
2. Then in terminal
GUIX_PACKAGE_PATH=/home/jone/sys.cfg/build/my/ guix package -i
xfce4-cpugraph-plugin
ERROR: In procedure %resolve-variable:
libxfce4util: unbound variable