mixxx: patch to build with gcc6 (via debian)

Also, get the sqlite patch directly from bugs.gentoo.org.

pkgs/applications/audio/mixxx/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, fetchurl, chromaprint, fftw, flac, libid3tag, libmad
+{ stdenv, fetchurl, chromaprint, fetchpatch, fftw, flac, libid3tag, libmad
 , libopus, libshout, libsndfile, libusb1, libvorbis, pkgconfig
 , portaudio, portmidi, protobuf, qt4, rubberband, scons, sqlite
 , taglib, vampSDK
@@ -13,7 +13,17 @@ stdenv.mkDerivation rec {
     sha256 = "0vb71w1yq0xwwsclrn2jj9bk8w4n14rfv5c0aw46c11mp8xz7f71";
   };
 
-  patches = [ ./sqlite.patch ]; # from: https://bugs.gentoo.org/show_bug.cgi?id=622776
+  patches = [
+    (fetchpatch {
+      url = "https://sources.debian.net/data/main/m/mixxx/2.0.0~dfsg-7.1/debian/patches/0007-fix_gcc6_issue.patch";
+      sha256 = "0kpyv10wcjcvbijk6vpq54gx9sqzrq4kq2qilc1czmisp9qdy5sd";
+    })
+    (fetchpatch {
+      url = "https://622776.bugs.gentoo.org/attachment.cgi?id=487284";
+      name = "sqlite.patch";
+      sha256 = "1qqbd8nrxrjcc1dwvyqfq1k2yz3l071sfcgd2dmpk6j8d4j5kx31";
+    })
+ ];
 
   buildInputs = [
     chromaprint fftw flac libid3tag libmad libopus libshout libsndfile

pkgs/applications/audio/mixxx/sqlite.patch

@@ -1,13 +0,0 @@
-diff -urN old/src/library/trackcollection.h mixxx-2.0.0/src/library/trackcollection.h
---- old/src/library/trackcollection.h	2017-07-30 00:04:48.511029517 -0400
-+++ mixxx-2.0.0/src/library/trackcollection.h	2017-07-30 00:05:03.378699826 -0400
-@@ -34,8 +34,7 @@
- #include "library/dao/libraryhashdao.h"
-
- #ifdef __SQLITE3__
--typedef struct sqlite3_context sqlite3_context;
--typedef struct Mem sqlite3_value;
-+#include <sqlite3.h>
- #endif
-
- class TrackInfoObject;