install gcc-riscv64-linux-gnu

Makefile

@@ -14,7 +14,7 @@ all: keystone opensbi
 # Build a linux image with the keystone driver
 keystone:
 	sudo apt-get update
-	sudo apt install autoconf automake autotools-dev bc bison build-essential curl expat libexpat1-dev flex gawk gcc git gperf libgmp-dev libmpc-dev libmpfr-dev libtool texinfo tmux patchutils zlib1g-dev wget bzip2 patch vim-common lbzip2 python3 pkg-config libglib2.0-dev libpixman-1-dev libssl-dev device-tree-compiler expect makeself unzip
+	sudo apt install autoconf automake autotools-dev bc bison build-essential curl expat libexpat1-dev flex gawk gcc git gperf libgmp-dev libmpc-dev libmpfr-dev libtool texinfo tmux patchutils zlib1g-dev wget bzip2 patch vim-common lbzip2 python3 pkg-config libglib2.0-dev libpixman-1-dev libssl-dev device-tree-compiler expect makeself unzip gcc-riscv64-linux-gnu
 
 	-git clone https://github.com/keystone-enclave/keystone.git
 	cd keystone \