Update README instructions (and adapt Makefile)

Makefile

@@ -23,13 +23,13 @@ build-ebpf:
 		ebpf/main.c \
 		-c -o - | llc -march=bpf -filetype=obj -o ebpf/bin/probe.o
 
-build:
+build: build-ebpf
 	go build -o $(NAME) .
 
-build-with-sound:
+build-with-sound: build-ebpf
 	go build -tags libasound -o $(NAME) .
 
-all: build-ebpf build
+all: build
 
 clean:
 	find . -name "*~"|xargs rm -f
@@ -38,3 +38,6 @@ clean:
 
 run: $(NAME)
 	sudo ./$(NAME)
+
+run-with-sound: build-with-sound
+	sudo ./$(NAME)

README.md

@@ -8,6 +8,11 @@ This is just a fun konami code easter egg in ebpf
 
 > make run
 
+And with some sound (requires `libasound2-dev` installed):
+
+> make run-with-sound
+
+
 ## What it does
 
-When you succeed to enter the konami code, it will open the wikipedia page (and may be play a sound, if you have `libasound2-dev` installed).
+When you succeed to enter the konami code, it will open the wikipedia page.