gnu: Add libepoxy.

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

Modified-By: Mark H Weaver <mhw@netris.org>

gnu/packages/gl.scm

@@ -418,3 +418,50 @@ extension functionality is exposed in a single header file.")
      "Guile-OpenGL is a library for Guile that provides bindings to the
 OpenGL graphics API.")
     (license l:lgpl3+)))
+
+(define-public libepoxy
+  (package
+    (name "libepoxy")
+    (version "1.2")
+    (source (origin
+              (method url-fetch)
+              (uri (string-append
+                    "https://github.com/anholt/libepoxy/archive/v"
+                    version
+                    ".tar.gz"))
+              (file-name (string-append name "-" version ".tar.gz"))
+              (sha256
+               (base32
+                "1xp8g6b7xlbym2rj4vkbl6xpb7ijq7glpv656mc7k9b01x22ihs2"))))
+    (arguments
+     '(#:phases
+       (alist-cons-after
+        'unpack 'autoreconf
+        (lambda _
+          (zero? (system* "autoreconf" "-vif")))
+        (alist-cons-before
+         'configure 'patch-paths
+         (lambda* (#:key inputs #:allow-other-keys)
+           (let ((python (assoc-ref inputs "python"))
+                 (mesa (assoc-ref inputs "mesa")))
+             (substitute* "src/gen_dispatch.py"
+               (("/usr/bin/env python") python))
+             (substitute* (find-files "." "\\.[ch]$")
+               (("libGL.so.1") (string-append mesa "/lib/libGL.so.1"))
+               (("libEGL.so.1") (string-append mesa "/lib/libEGL.so.1")))
+             #t))
+         %standard-phases))))
+    (build-system gnu-build-system)
+    (native-inputs
+     `(("autoconf" ,autoconf)
+       ("automake" ,automake)
+       ("libtool" ,libtool)
+       ("pkg-config" ,pkg-config)
+       ("python" ,python)))
+    (inputs
+     `(("mesa" ,mesa)))
+    (home-page "http://github.com/anholt/libepoxy/")
+    (synopsis "A library for handling OpenGL function pointer management")
+    (description
+     "A library for handling OpenGL function pointer management.")
+    (license l:x11)))