gnu: Fix package references.

* gnu/packages/algebra.scm (iml)[inputs]: Correctly refer to package
inputs.
* gnu/packages/astronomy.scm (xplanet),
* gnu/packages/audio.scm (redkite, libaudec, lv2lint, lv2toweb),
* gnu/packages/bioconductor.scm (r-cummerbund),
* gnu/packages/chicken.scm (chicken),
* gnu/packages/conky.scm (conky),
* gnu/packages/cran.scm (r-latex2exp),
* gnu/packages/crates-io.scm (rust-rgb),
* gnu/packages/databases.scm (mariadb),
* gnu/packages/diffoscope.scm (reprotest),
* gnu/packages/file-systems.scm (glusterfs),
* gnu/packages/finance.scm (electron-cash),
* gnu/packages/games.scm (rinutils, ksudoku, kdiamond, kigo),
* gnu/packages/geo.scm (grass),
* gnu/packages/gnome.scm (libmediaart, gnome-contacts, geoclue),
* gnu/packages/gnucash.scm (aqbanking),
* gnu/packages/image.scm (mtpaint),
* gnu/packages/kde-internet.scm (kopete, ktorrent),
* gnu/packages/kde-utils.scm (kmousetool, kmouth, kronometer),
* gnu/packages/linphone.scm (liblinphone),
* gnu/packages/maths.scm (ppl),
* gnu/packages/mercury.scm (mercury-minimal),
* gnu/packages/music.scm (bjumblr, bschaffl, lsp-plugins,
spectacle-analyzer, helm, tap-lv2, wolf-shaper, shiru-lv2),
* gnu/packages/networking.scm (restinio),
* gnu/packages/prolog.scm (swi-prolog),
* gnu/packages/python-web.scm (gunicorn),
* gnu/packages/python-xyz.scm (python-docusign-esign),
* gnu/packages/ruby.scm (ruby-cucumber, ruby_version, ruby-addressable),
* gnu/packages/sagemath.scm (python-cypari2),
* gnu/packages/skarnet.scm (s6-linux-init),
* gnu/packages/vpn.scm (sshuttle),
* gnu/packages/web.scm (libcyaml),
* gnu/packages/xdisorg.scm (kbdd),
* gnu/packages/xorg.scm (xpra): Same.

gnu/packages/audio.scm

@@ -4519,7 +4519,7 @@ workstations as well as consumer software such as music players.")
     (inputs
      `(("cairo" ,cairo)))
     (native-inputs
-     `(("pkg-config", pkg-config)))
+     `(("pkg-config" ,pkg-config)))
     (synopsis "Small GUI toolkit")
     (description "Redkite is a small GUI toolkit developed in C++17 and
 inspired from other well known GUI toolkits such as Qt and GTK.  It is
@@ -4665,7 +4665,7 @@ in the package.")
     `(("libsamplerate" ,libsamplerate)
       ("libsndfile" ,libsndfile)))
    (native-inputs
-     `(("pkg-config", pkg-config)))
+     `(("pkg-config" ,pkg-config)))
    (synopsis "Library for reading and resampling audio files")
    (description "libaudec is a wrapper library over ffmpeg, sndfile and
 libsamplerate for reading and resampling audio files, based on Robin Gareus'
@@ -4693,11 +4693,11 @@ libsamplerate for reading and resampling audio files, based on Robin Gareus'
        `("-Delf-tests=true" ; for checking symbol visibility
          "-Donline-tests=true"))) ; for checking URI existence
     (inputs
-      `(("curl", curl)
-        ("libelf", libelf)
-        ("lilv", lilv)))
+      `(("curl" ,curl)
+        ("libelf" ,libelf)
+        ("lilv" ,lilv)))
     (native-inputs
-      `(("pkg-config", pkg-config)))
+      `(("pkg-config" ,pkg-config)))
     (synopsis "LV2 plugin lint tool")
     (description "lv2lint is an LV2 lint-like tool that checks whether a
 given plugin and its UI(s) match up with the provided metadata and adhere
@@ -4728,11 +4728,11 @@ to well-known best practices.")
       (modify-phases %standard-phases
         (delete 'configure))))
     (inputs
-      `(("jalv", jalv)
-        ("lilv", lilv)))
+      `(("jalv" ,jalv)
+        ("lilv" ,lilv)))
     (native-inputs
-      `(("help2man", help2man)
-        ("pkg-config", pkg-config)))
+      `(("help2man" ,help2man)
+        ("pkg-config" ,pkg-config)))
     (synopsis "Documentation generator for LV2 plugins")
     (description
       "lv2toweb allows the user to create an xhtml page with information