Make best use of the compiler, and enable -Wextra as well as -Wall. There are a few issues that had to be resolved, but they are all trivial.
Follow these steps to get DRAMSim2 as part of gem5
1. Download DRAMSim2
1.1 Go to ext/dramsim2 (this directory)
1.2 Clone DRAMSim2: git clone git://github.com/dramninjasUMD/DRAMSim2.git
2. Compile gem5
2.1 Business as usual
3. Run gem5 with DRAMSim2
3.1 Use --mem-type=dramsim2 and set the device and system configuration