Auto-generate the getevent labels from <linux/input.h>.

Now we only have to remember to update the kernel uapi headers, which
we're pretty good at.

Change-Id: If04eb8c50882fff5e5e2a5d72664f5d4c4c538b1
diff --git a/toolbox/getevent.c b/toolbox/getevent.c
index c58eb5d..30053af 100644
--- a/toolbox/getevent.c
+++ b/toolbox/getevent.c
@@ -12,7 +12,25 @@
 #include <errno.h>
 #include <unistd.h>
 
-#include "getevent.h"
+struct label {
+    const char *name;
+    int value;
+};
+
+#define LABEL(constant) { #constant, constant }
+#define LABEL_END { NULL, -1 }
+
+static struct label key_value_labels[] = {
+        { "UP", 0 },
+        { "DOWN", 1 },
+        { "REPEAT", 2 },
+        LABEL_END,
+};
+
+#include "input.h-labels.h"
+
+#undef LABEL
+#undef LABEL_END
 
 static struct pollfd *ufds;
 static char **device_names;