gem5 build system improved

Encapsulated gem5-specific code into wrapper functions to separate the
build process (Fail: CMake, gem5: scons). Added some gem5-related FIXMEs.

Another CMake related FIXME added. +some cosmetics.

Change-Id: Id84b480127b1f13aed6a0ee97f3583f410d531c5

src/core/sal/gem5/Gem5Wrapper.hpp

@@ -0,0 +1,33 @@
+#ifndef __GEM5_WRAPPER_HPP__
+  #define __GEM5_WRAPPER_HPP__
+
+#include "../Register.hpp"
+#include "../SALConfig.hpp"
+
+// gem5 forward declarations:
+class System;
+
+namespace fail {
+
+class Gem5Breakpoint;
+
+// Register-/Memory-related:
+regdata_t GetRegisterContent(System* sys, unsigned int id, RegisterType type, size_t idx);
+void SetRegisterContent(System* sys, unsigned int id, RegisterType type, size_t idx,
+                        regdata_t value);
+void WriteMemory(System* sys, guest_address_t addr, size_t cnt, void const *src);
+void ReadMemory(System* sys, guest_address_t addr, size_t cnt, void *dest);
+size_t GetPoolSize(System* sys);
+
+// Breakpoint-related:
+Gem5Breakpoint* OnBreakpointAddition(address_t watchInstrPtr);
+void OnBreakpointDeletion(Gem5Breakpoint* bp);
+
+// Controller-related:
+unsigned int GetCPUId(System* sys, int context);
+System* GetSystemObject();
+int GetNumberOfContexts(System* sys);
+
+} // end-of-namespace: fail
+
+#endif // __GEM5_WRAPPER_HPP__