Compile to static executable

Makefile

@@ -6,7 +6,7 @@ spike:
 	# Unfortunately there is no tag on the Spike repo, so we pick the latest
 	-git clone --depth 1 https://github.com/riscv-software-src/riscv-isa-sim.git
 	mkdir build
-	cd build && ../riscv-isa-sim/configure && make -j `nproc` && cp spike ../
+	cd build && ../riscv-isa-sim/configure CFLAGS=-static CXXFLAGS="-static -static-libgcc -static-libstdc++" LDFLAGS=-static && make -j `nproc` spike && cp spike ../
 
 clean:
 	-rm -rf build riscv-isa-sim spike