gnu: mit-krb5: don't assume arguments are evaluated right-to-left.

* gnu/packages/patches/mit-krb5-init-fix.patch: New file.
* gnu/packages/mit-krb5.scm (mit-krb5): Apply patch at the end of the custom
  unpack phase.
* gnu-system.am (dist_patch_DATA): Add patch.

gnu-system.am

@@ -251,6 +251,7 @@ dist_patch_DATA =						\
   gnu/packages/patches/m4-readlink-EINVAL.patch			\
   gnu/packages/patches/make-impure-dirs.patch			\
   gnu/packages/patches/mcron-install.patch			\
+  gnu/packages/patches/mit-krb5-init-fix.patch			\
   gnu/packages/patches/perl-no-sys-dirs.patch			\
   gnu/packages/patches/plotutils-libpng-jmpbuf.patch		\
   gnu/packages/patches/procps-make-3.82.patch			\

gnu/packages/mit-krb5.scm

@@ -37,6 +37,8 @@
             (sha256 (base32
                      "1daiaxgkxcryqs37w28v4x1vajqmay4l144d1zd9c2d7jjxr9gcs"))))
    (build-system gnu-build-system)
+   (native-inputs
+    `(("patch/init-fix" ,(search-patch "mit-krb5-init-fix.patch"))))
    (inputs `(("bison" ,bison)
              ("perl" ,perl)))
    (arguments
@@ -51,7 +53,12 @@
            (and (zero? (system* "tar" "xvf" source))
                 (zero? (system* "tar" "xvf" (string-append inner ".tar.gz")))
                 (chdir inner)
-                (chdir "src"))))
+                (chdir "src")
+                ;; XXX The current patch system does not support unusual
+                ;; source unpack methods, so we have to apply this patch in a
+                ;; non-standard way.
+                (zero? (system* "patch" "-p1" "--batch" "-i"
+                                (assoc-ref %build-inputs "patch/init-fix"))))))
        (alist-replace
         'check
         (lambda* (#:key inputs #:allow-other-keys #:rest args)

gnu/packages/patches/mit-krb5-init-fix.patch

@@ -0,0 +1,18 @@
+Fix the early context initialization code to avoid assuming that
+arguments will be evaluated from right to left.
+
+Patch by Mark H Weaver <mhw@netris.org>.
+
+--- src/lib/krb5/krb/t_cc_config.c.orig	2012-12-17 21:47:05.000000000 -0500
++++ src/lib/krb5/krb/t_cc_config.c	2013-10-29 18:19:16.547994590 -0400
+@@ -117,8 +117,8 @@
+     int c;
+     unsigned int i;
+ 
+-    bail_on_err(context, "Error initializing Kerberos library",
+-                krb5_init_context(&context));
++    ret = krb5_init_context(&context);
++    bail_on_err(context, "Error initializing Kerberos library", ret);
+     bail_on_err(context, "Error getting location of default ccache",
+                 krb5_cc_default(context, &ccache));
+     server = NULL;