Source Level Debugger - debugger library interface

- interface to debugger dynamic library
- code is included when source level debugger header exists,
otherwise implementation is exluded from build
- unit tests do not load real dynamic library,
instead test version (DebbugerLibrary) of OsLibrary is used.

Change-Id: Id3229c77963352e8001043ee41b7d48c6b180a59

runtime/os_interface/linux/source_level_debugger_linux.cpp

@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2018, Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include "runtime/source_level_debugger/source_level_debugger.h"
+
+const char *OCLRT::SourceLevelDebugger::dllName = "libigfxdbgxchg64.so";