This patch fixes a typo in the SConscript which caused the DRAMSim2 sources to be built without the appropriate flags.
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