Add TODO

ed.c

@@ -1,4 +1,25 @@
 /* See LICENSE file for copyright and license details. */
+
+/*
+ * TODO: Multi-line commands don't work in global commands:
+ * o  g/^line/a \
+ *    line1
+ *    .
+ * o  Signal handling is broken
+ * o  cat <<EOF | ed
+ *    0a
+ *    int radix = 16;
+ *    int Pflag;
+ *    int Aflag;
+ *    int vflag;
+ *    int gflag;
+ *    int uflag;
+ *    int arflag;
+ *
+ *    .
+ *    ?radix?;/^$/-s/^/static /
+ */
+
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <regex.h>