Add simple makefile

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..24a5cf4
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,5 @@
+
+CC = gcc
+CFLAGS = -Wall -Wextra -Werror
+
+all: inarp