common: move some files out of lightningd/

Basically all files shared by different daemons.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

common/debug.c

@@ -0,0 +1,30 @@
+#include <ccan/str/str.h>
+#include <common/debug.h>
+#include <common/dev_disconnect.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+void subdaemon_debug(int argc, char *argv[])
+{
+	int i;
+	bool printed = false;
+
+	for (i = 1; i < argc; i++) {
+		if (strstarts(argv[i], "--dev-disconnect=")) {
+			dev_disconnect_init(atoi(argv[i]
+						 + strlen("--dev-disconnect=")));
+		}
+	}
+
+	/* From debugger, tell gdb "return". */
+	for (i = 1; i < argc; i++) {
+		while (streq(argv[i], "--debugger")) {
+			if (!printed)
+				fprintf(stderr, "gdb -ex 'attach %u' %s\n",
+					getpid(), argv[0]);
+			printed = true;
+		}
+	}
+}