gnu: kpackage: Transfer patches from NixOS.

Transfer the NixOS patches for kpackage as of 2018-02-17:
- Allow external paths.
- Make QDirIterator follow symlinks.

Decided to use a patch for one of the "allow external paths" changes since
'substitute*' seems not to be robust enough.

* gnu/packages/patches/kpackage-allow-external-paths.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/kde-frameworks.scm(kpackage)[source]: Use it. <patch>: New
  phase.

gnu/local.mk

@@ -859,6 +859,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/kinit-kdeinit-libpath.patch		\
   %D%/packages/patches/kio-search-smbd-on-PATH.patch		\
   %D%/packages/patches/kmod-module-directory.patch		\
+  %D%/packages/patches/kpackage-allow-external-paths.patch	\
   %D%/packages/patches/kobodeluxe-paths.patch			\
   %D%/packages/patches/kobodeluxe-enemies-pipe-decl.patch	\
   %D%/packages/patches/kobodeluxe-const-charp-conversion.patch	\

gnu/packages/kde-frameworks.scm

@@ -1825,7 +1825,10 @@ covers feedback and persistent events.")
                     name "-" version ".tar.xz"))
               (sha256
                (base32
-                "1xbfjwxb4gff8gg0hs5m9s0jcnzqk27rs2jr71g5ckhvs5psnkcd"))))
+                "1xbfjwxb4gff8gg0hs5m9s0jcnzqk27rs2jr71g5ckhvs5psnkcd"))
+              ;; Default to: external paths/symlinks can be followed by a
+              ;; package
+              (patches (search-patches "kpackage-allow-external-paths.patch"))))
     (build-system cmake-build-system)
     (native-inputs
      `(("extra-cmake-modules" ,extra-cmake-modules)))
@@ -1840,6 +1843,16 @@ covers feedback and persistent events.")
      `(#:tests? #f ; FIXME: 3/9 tests fail.
        #:phases
        (modify-phases %standard-phases
+         (add-after 'unpack 'patch
+           (lambda _
+             ;; Make QDirIterator follow symlinks
+             (substitute* '("src/kpackage/packageloader.cpp"
+                            "src/kpackage/private/packagejobthread.cpp")
+               (("^\\s*(const QDirIterator::IteratorFlags flags = QDirIterator::Subdirectories)(;)" _ a b)
+                (string-append a " | QDirIterator::FollowSymlinks" b))
+               (("^\\s*(QDirIterator it\\(.*, QDirIterator::Subdirectories)(\\);)" _ a b)
+                (string-append a " | QDirIterator::FollowSymlinks" b)))
+             #t))
          (add-before 'check 'check-setup
            (lambda _
              (setenv "HOME" (getcwd))

gnu/packages/patches/kpackage-allow-external-paths.patch

@@ -0,0 +1,13 @@
+diff --git a/src/kpackage/package.cpp b/src/kpackage/package.cpp
+index 5aec9fd..b15c933 100644
+--- a/src/kpackage/package.cpp
++++ b/src/kpackage/package.cpp
+@@ -820,7 +820,7 @@ PackagePrivate::PackagePrivate()
+     : QSharedData(),
+       fallbackPackage(nullptr),
+       metadata(nullptr),
+-      externalPaths(false),
++      externalPaths(true),
+       valid(false),
+       checkedValid(false)
+ {