replace asprintf in package openscenegraph

MinGW does not provide asprintf. We could get it from gnulib
or liberty, but in this case it's easy reimplement the section.

src/openscenegraph-3-no-asprintf.patch

@@ -0,0 +1,25 @@
+This file is part of mingw-cross-env.
+See doc/index.html for further information.
+
+diff -urN a/src/osgPlugins/xine/ReaderWriterXine.cpp b/src/osgPlugins/xine/ReaderWriterXine.cpp
+--- a/src/osgPlugins/xine/ReaderWriterXine.cpp	2010-03-13 11:38:10.000000000 +0100
++++ b/src/osgPlugins/xine/ReaderWriterXine.cpp	2010-04-27 12:21:20.597790305 +0200
+@@ -326,9 +326,15 @@
+             const char* user_home = xine_get_homedir();
+             if(user_home)
+             {
+-                char* cfgfile = NULL;
+-                int result = asprintf(&(cfgfile), "%s/.xine/config", user_home);                
+-                if (result>0) xine_config_load(_xine, cfgfile);
++                const char* tail = "/.xine/config";
++                int size = strlen(user_home) + strlen(tail) + 1;
++                char* cfgfile = malloc(size);
++                if (cfgfile)
++                {
++                    strcpy(cfgfile, user_home);
++                    strcat(cfgfile, tail);               
++                    xine_config_load(_xine, cfgfile);
++                }
+             }
+ 
+             xine_init(_xine);