These are the differences between sed.c 1.15 and sed.c 1.16.  
They are all bug fixes and standard-conformance fixes.

*** Start "gdiff -u ../sed-1.15/sed.c sed.c" in /afs/andrew.cmu.edu/usr11/lord/fsf/sed-1.16/ at 12:38:56
--- ../sed-1.15/sed.c	Fri May 21 01:40:49 1993
+++ sed.c	Sat May 22 19:59:52 1993
@@ -21,6 +21,7 @@
 #define VOID char
 #endif
 
+
 #define _GNU_SOURCE
 #include <ctype.h>
 #ifndef isblank
@@ -67,7 +68,7 @@
 #endif
 #endif
 
-char *version_string = "GNU sed version 1.15";
+char *version_string = "GNU sed version 1.16";
 
 /* Struct vector is used to describe a chunk of a compiled sed program.  
  * There is one vector for the main program, and one for each { } pair,
@@ -257,7 +258,7 @@
 void line_copy P_ ((struct line * from, struct line * to));
 void line_append P_ ((struct line * from, struct line * to));
 void str_append P_ ((struct line * to, char *string, int length));
-void usage P_ ((void));
+void usage P_ ((int));
 
 extern char *myname;
 
@@ -355,6 +356,7 @@
   {"quiet", 0, NULL, 'n'},
   {"silent", 0, NULL, 'n'},
   {"version", 0, NULL, 'V'},
+  {"help", 0, NULL, 'h'},
   {NULL, 0, NULL, 0}
 };
 
@@ -371,9 +373,8 @@
   /* see regex.h */
   re_set_syntax (RE_SYNTAX_POSIX_BASIC);
 
-
   myname = argv[0];
-  while ((opt = getopt_long (argc, argv, "ne:f:V", longopts, (int *) 0))
+  while ((opt = getopt_long (argc, argv, "hne:f:V", longopts, (int *) 0))
 	 != EOF)
     {
       switch (opt)
@@ -403,8 +404,12 @@
 	  fprintf (stderr, "%s\n", version_string);
 	  exit (0);
 	  break;
+	case 'h':
+	  usage (0);
+	  break;
 	default:
-	  usage ();
+	  usage (4);
+	  break;
 	}
     }
   if (e_strings)
@@ -415,7 +420,7 @@
   if (!compiled)
     {
       if (optind == argc)
-	usage ();
+	usage (4);
       compile_string (argv[optind++]);
     }
 
@@ -528,7 +533,7 @@
      int open_line;
 {
   struct sed_cmd *cur_cmd;
-  int ch;
+  int ch, pch;
   int slash;
   VOID *b;
   unsigned char *string;
@@ -548,8 +553,9 @@
     skip_comment:
       do
 	{
+	  pch = ch;
 	  ch = inchar ();
-	  if (ch == '\\')
+	  if ((pch == '\\') && (ch == '\n'))
 	    ch = inchar ();
 	}
       while (ch != EOF && (isblank (ch) || ch == '\n' || ch == ';'));
@@ -1781,13 +1787,6 @@
 	    input_EOF++;
 	  return;
 	}
-      *p++ = ch;
-      --n;
-      if (ch == '\n')
-	{
-	  line.length = line.alloc - n;
-	  break;
-	}
       if (n == 0)
 	{
 	  line.text = ck_realloc (line.text, line.alloc * 2);
@@ -1795,6 +1794,13 @@
 	  n = line.alloc;
 	  line.alloc *= 2;
 	}
+      *p++ = ch;
+      --n;
+      if (ch == '\n')
+	{
+	  line.length = line.alloc - n;
+	  break;
+	}
     }
   ch = getc (input_file);
   if (ch != EOF)
@@ -1853,11 +1859,12 @@
 }
 
 void
-usage ()
+usage (status)
+     int status;
 {
-  fprintf (stderr, "\
+  fprintf (status ? stderr : stdout, "\
 Usage: %s [-nV] [--quiet] [--silent] [--version] [-e script]\n\
         [-f script-file] [--expression=script] [--file=script-file] [file...]\n",
 	   myname);
-  exit (4);
+  exit (status);
 }