WIP recipe for an updated version of MuseScore.

Fails to build, if anyone feels like giving some help, that would be
great.

media-sound/musescore/patches/musescore-3.2.3.patchset

@@ -0,0 +1,51 @@
+From 9e7431905e99d10a34107f5fbdb0cff79223f2ff Mon Sep 17 00:00:00 2001
+From: Adrien Destugues <pulkomandy@pulkomandy.tk>
+Date: Tue, 17 Sep 2019 19:09:55 +0200
+Subject: Import still relevant part of Haiku patches.
+
+
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index 93eaafa..6f116e2 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -114,6 +114,13 @@ if (APPLE)
+       option(BUILD_ALSA ${MAC_NOT_AVAIL} OFF)
+ endif (APPLE)
+ 
++# Disable components not supported on Mac
++if (HAIKU)
++	set(HAIKU_NOT_AVAIL "Not available on Haiku")
++	option(BUILD_PULSEAUDIO ${HAIKU_NOT_AVAIL} OFF)
++	option(BUILD_ALSA ${HAIKU_NOT_AVAIL} OFF)
++endif (HAIKU)
++
+ # Disable components not supported on Linux/BSD
+ if (NOT APPLE AND NOT MINGW AND NOT MSVC)
+       set(NIX_NOT_AVAIL "Not available on Linux/BSD")
+diff --git a/mscore/CMakeLists.txt b/mscore/CMakeLists.txt
+index 8033b35..5a8c314 100644
+--- a/mscore/CMakeLists.txt
++++ b/mscore/CMakeLists.txt
+@@ -768,8 +768,6 @@ else (MINGW)
+ 
+       if (APPLE)
+         target_link_libraries(mscore ${OsxFrameworks})
+-      else (APPLE)
+-          target_link_libraries(mscore rt)
+       endif (APPLE)
+ 
+       # 'gold' does not use indirect shared libraries for symbol resolution, Linux only
+@@ -777,7 +775,9 @@ else (MINGW)
+          if(USE_JACK)
+             target_link_libraries(mscore ${CMAKE_DL_LIBS})
+          endif(USE_JACK)
+-         target_link_libraries(mscore rt)
++		 if (NOT HAIKU)
++         	target_link_libraries(mscore rt)
++		 endif(NOT HAIKU)
+       endif (NOT APPLE)
+ 
+       if (APPLE)
+-- 
+2.23.0
+