gnu: Add telegram-purple.

* gnu/packages/messaging.scm (telegram-purple): New variable.
* gnu/packages/patches/telegram-purple-adjust-test.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.

Co-authored-by: Ludovic Courtès <ludo@gnu.org>

gnu/local.mk

@@ -1166,6 +1166,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/tcsh-fix-out-of-bounds-read.patch	\
   %D%/packages/patches/teensy-loader-cli-help.patch		\
   %D%/packages/patches/teeworlds-use-latest-wavpack.patch	\
+  %D%/packages/patches/telegram-purple-adjust-test.patch	\
   %D%/packages/patches/texi2html-document-encoding.patch	\
   %D%/packages/patches/texi2html-i18n.patch			\
   %D%/packages/patches/thefuck-test-environ.patch		\

gnu/packages/messaging.scm

@@ -1763,4 +1763,86 @@ non-interoperable protocol, which allows it to support features like group
 messaging that aren’t available to clients that connect over XMPP.")
     (license license:expat)))
 
+(define-public telegram-purple
+  (package
+    (name "telegram-purple")
+    (version "1.3.1")
+    (home-page "https://github.com/majn/telegram-purple")
+    (source (origin
+              (method git-fetch)
+              (uri (git-reference
+                    (url home-page)
+                    (commit (string-append "v" version))
+                    (recursive? #t)))
+              (sha256
+               (base32
+                "0p93jpjpx7hszwffzgixw04zkrpsiyzz4za3gfr4j07krc4771fp"))
+              (modules '((guix build utils)))
+              (snippet
+               '(begin
+                  (substitute* "Makefile.in"
+                    ;; By default these two directories point to Pidgin's own
+                    ;; prefix.
+                    (("^PLUGIN_DIR_PURPLE=.*")
+                     (string-append
+                      "exec_prefix := @exec_prefix@\n"
+                      "PLUGIN_DIR_PURPLE := @libdir@/purple-2\n"))
+                    (("^DATA_ROOT_DIR_PURPLE=.*")
+                     "DATA_ROOT_DIR_PURPLE := @datarootdir@\n")
+
+                    ;; Honor sysconfdir instead of trying to write to /etc.
+                    (("DESTDIR\\)/etc/telegram-purple")
+                     "DESTDIR)@sysconfdir@/telegram-purple"))
+                  #t))
+              (patches (search-patches "telegram-purple-adjust-test.patch"))
+              (file-name (git-file-name name version))))
+    (build-system gnu-build-system)
+    (native-inputs
+     `(("pkg-config" ,pkg-config)
+       ("which" ,which)))
+    (inputs
+     `(("pidgin" ,pidgin)
+       ("libgcrypt" ,libgcrypt)
+       ("libwebp" ,libwebp)
+       ("glib" ,glib)
+       ("gettext" ,gnu-gettext)
+       ("gtk+" ,gtk+-2)
+       ("zlib" ,zlib)))
+    (arguments
+     `(#:phases
+       (modify-phases %standard-phases
+         ;; We're using release tag for repository checkout - let's prepare
+         ;; header defining GIT_COMMIT manually instead of running git to
+         ;; identify version which is being compiled. Git repository
+         ;; is removed anyway and only source code is kept.
+         (add-after 'unpack 'prepare-commit.h
+           (lambda _
+             (with-output-to-file "./commit.h"
+               (lambda ()
+                 (display
+                  (string-append "//generated by guix, use version instead of "
+                                 "commit\n"
+                                 "#ifndef GIT_COMMIT\n"
+                                 "#  define GIT_COMMIT \"v"
+                                 ,version "\"\n"
+                                 "#endif\n"))))
+             #t))
+         (add-before 'configure 'set-SHELL-variables
+           ;; Set these environment variables so that 'tgl/configure' uses the
+           ;; right shell and not /bin/sh.
+           (lambda _
+             (let ((bash (which "bash")))
+               (setenv "SHELL" bash)
+               (setenv "CONFIG_SHELL" bash)
+               #t))))))
+    (synopsis "Telegram messaging support for Pidgin")
+    (description
+     "Telegram-purple is a plugin for Libpurple, the communication library
+used by the Pidgin instant messaging client, that adds support for the
+Telegram messenger.")
+
+    ;; Code under tgl/ (the Telegram library) is LGPLv2.1+, but the plugin
+    ;; itself is GPLv2+.
+    (license license:gpl2+)))
+
 ;;; messaging.scm ends here

gnu/packages/patches/telegram-purple-adjust-test.patch

@@ -0,0 +1,14 @@
+This test incorrectly expects the libpurple search path to initially
+contain exactly one element.  Remove this incorrect assertion.
+
+--- telegram-purple-1.3.1-checkout/test/loadtest.c	2018-10-27 16:25:06.258459600 +0200
++++ telegram-purple-1.3.1-checkout/test/loadtest.c	2018-10-27 16:25:11.830434770 +0200
+@@ -156,7 +156,7 @@ static void tdf_inject_plugin (void) {
+   printf ("Injecting our module into purple_plugins_* ...\n");
+   purple_plugins_init ();
+   GList *search_paths = purple_plugins_get_search_paths ();
+-  assert (!search_paths->prev && !search_paths->next && search_paths->data);
++  assert (!search_paths->prev && search_paths->data);
+   GList *new_paths = g_list_append (search_paths, g_strdup ("bin/"));
+   assert (new_paths == search_paths);
+   // Load "my" path before the default.