openscenegraph: add missing gstreamer dep and fix detection on mingw

src/openscenegraph-1-fixes.patch

@@ -135,3 +135,23 @@ index 1111111..2222222 100644
          osg
          osgDB
          osgUtil
+
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Tony Theodore <tonyt@logyst.com>
+Date: Sun, 10 Jan 2016 14:19:57 +1100
+Subject: [PATCH] use pkg-config for gstreamer detection in mingw
+
+
+diff --git a/CMakeModules/FindGStreamer.cmake b/CMakeModules/FindGStreamer.cmake
+index 1111111..2222222 100644
+--- a/CMakeModules/FindGStreamer.cmake
++++ b/CMakeModules/FindGStreamer.cmake
+@@ -65,7 +65,7 @@
+ #    )
+ #endmacro()
+ 
+-if (WIN32)
++if (WIN32 AND NOT MINGW)
+     macro(FIND_GSTREAMER_COMPONENT _component_prefix _pkgconfig_name _header _library)
+         find_path(${_component_prefix}_INCLUDE_DIRS
+             NAMES ${_header}

src/openscenegraph.mk

@@ -8,7 +8,9 @@ $(PKG)_CHECKSUM := 5c727d84755da276adf8c4a4a3a8ba9c9570fc4b4969f06f1d2e9f89b1e30
 $(PKG)_SUBDIR   := OpenSceneGraph-$($(PKG)_VERSION)
 $(PKG)_FILE     := OpenSceneGraph-$($(PKG)_VERSION).zip
 $(PKG)_URL      := http://trac.openscenegraph.org/downloads/developer_releases/$($(PKG)_FILE)
-$(PKG)_DEPS     := gcc boost curl dcmtk ffmpeg freetype gdal giflib gta jasper jpeg libpng openal openexr openthreads poppler qt tiff xine-lib zlib
+$(PKG)_DEPS     := gcc boost curl dcmtk ffmpeg freetype gdal giflib gstreamer \
+                   gta jasper jpeg libpng openal openexr openthreads poppler \
+                   qt tiff xine-lib zlib
 
 define $(PKG)_UPDATE
     $(WGET) -q -O- 'http://trac.openscenegraph.org/downloads/developer_releases/?C=M;O=D' | \