add support for forcibly closing cached files (needed when closing all active sounds before resetting openal)

This was SVN commit r1261.

source/lib/res/h_mgr.cpp

@@ -716,6 +716,15 @@ Handle h_find(H_Type type, uintptr_t key)
 }
 
 
+int h_allow_free(Handle h, H_Type type)
+{
+	HDATA* hd = h_data(h, type);
+	if(!hd)
+		return ERR_INVALID_HANDLE;
+	hd->keep_open = 0;
+	return 0;
+}
+
 
 
 int res_cur_scope;

source/lib/res/h_mgr.h

@@ -201,7 +201,10 @@ extern int h_reload(const char* fn);
 
 extern int res_cur_scope;
 
-
+// disable caching and allow the handle to actually be freed when refcount
+// is at 0. used when cached resources must be closed before exit,
+// e.g. sounds when reinitializing OpenAL (due to changed settings).
+extern int h_allow_free(Handle h, H_Type type);
 
 extern void h_mgr_shutdown();