Add prerequisites to getting started doc.

Change-Id: Id5e31752f30095660ddff20367e821d3e344c692
diff --git a/docs/GettingStarted.md b/docs/GettingStarted.md
index 4df0d23..a538e2e 100644
--- a/docs/GettingStarted.md
+++ b/docs/GettingStarted.md
@@ -23,6 +23,12 @@
 
 ## Compiling the hypervisor
 
+Install prerequisites:
+
+``` shell
+sudo apt install make binutils-aarch64-linux-gnu
+```
+
 By default, the hypervisor is built with clang for an aarch64 QEMU target by
 running: