gem5: codebase patched to compile with ag++

This changes allows us to compile the gem5 simulator with ag++. It
was tested with ag++ v0.8, built Apr 18 2013. Most of the changes
are preprocessor directives like #ifndef __puma which have been
inserted into the gem5 code. Unfortunately, a python script and a
SWIG input file have been patched, too.
Additionally, the CMake file has been updated. A single call to
"make" now invokes the ag++ (instead of the g++) compiler front
end. The new CMake target "gem5-allclean" should be used to clean
the current project when building FailGem5. In addition to cleaning
the Fail build directory, it also invokes "scons -c" in the gem5
build directory; that is, gem5 is cleaned as well.

Change-Id: I20a92f025f34f626b81e30f2c873baeba189f83b

simulators/gem5/src/sim/syscall_emul.hh

@@ -934,6 +934,7 @@ fstatfsFunc(SyscallDesc *desc, int callnum, LiveProcess *process,
         return -EBADF;
 
     struct statfs hostBuf;
+    int fstatfs(int fd, struct statfs *buf); // DanceOS (added forward decl.)
     int result = fstatfs(fd, &hostBuf);
 
     if (result < 0)