gnu: Add libglvnd.

* gnu/packages/gl.scm (libglvnd): New public variable.

gnu/packages/gl.scm

@@ -664,6 +664,53 @@ (define-public libepoxy
      "A library for handling OpenGL function pointer management.")
     (license license:x11)))
 
+(define-public libglvnd
+  (package
+    (name "libglvnd")
+    (version "1.3.1")
+    (home-page "https://gitlab.freedesktop.org/glvnd/libglvnd")
+    (source (origin
+              (method git-fetch)
+              (uri (git-reference
+                    (url home-page)
+                    (commit (string-append "v" version))))
+              (file-name (git-file-name name version))
+              (sha256
+               (base32
+                "0mkzdzdxjxjl794rblq4mq33wmb8ikqmfswbqdbr8gw2kw4wlhdl"))))
+    (build-system meson-build-system)
+    (arguments
+     '(#:configure-flags '("-Dx11=enabled")
+       #:phases (modify-phases %standard-phases
+                  (add-after 'unpack 'disable-glx-tests
+                    (lambda _
+                      ;; This package is meant to be used alongside Mesa.
+                      ;; To avoid a circular dependency, disable tests that
+                      ;; require a running Xorg server.
+                      (substitute* "tests/meson.build"
+                        (("if with_glx")
+                         "if false"))
+                      #t)))))
+    (native-inputs
+     `(("pkg-config" ,pkg-config)))
+    (inputs
+     `(("libx11" ,libx11)
+       ("libxext" ,libxext)
+       ("xorgproto" ,xorgproto)))
+    (synopsis "Vendor-neutral OpenGL dispatch library")
+    (description
+     "libglvnd is a vendor-neutral dispatch layer for arbitrating OpenGL
+API calls between multiple vendors.  It allows multiple drivers from
+different vendors to coexist on the same filesystem, and determines which
+vendor to dispatch each API call to at runtime.
+
+Both GLX and EGL are supported, in any combination with OpenGL and OpenGL ES.")
+    ;; libglvnd is available under a custom X11-style license, and incorporates
+    ;; code with various other licenses.  See README.md for details.
+    (license (list (license:x11-style "file://README.md")
+                   license:x11
+                   license:expat))))
+
 (define-public soil
   (package
     (name "soil")