Building mc/4.5.54 for SGI IRIX 6.5, I found that key.c was
incorrectly computing when it's buffer was full, as sizeof(int)
is not 1.  Here's a fix:

--- ./src/key.c	Sat Mar  3 17:33:25 2001
+++ ../mc-4.5.54/./src/key.c	Fri Sep 21 16:25:55 2001
@@ -370,7 +370,8 @@
 }
 
 /* The maximum sequence length (32 + null terminator) */
-static int seq_buffer [33];
+#define SEQ_BUFFER_LEN	33
+static int seq_buffer [SEQ_BUFFER_LEN];
 static int *seq_append = 0;
 
 static int push_char (int c)
@@ -378,7 +379,7 @@
     if (!seq_append)
 	seq_append = seq_buffer;
     
-    if (seq_append == &(seq_buffer [sizeof (seq_buffer)-2]))
+    if (seq_append == &(seq_buffer [SEQ_BUFFER_LEN - 2]))
 	return 0;
     *(seq_append++) = c;
     *seq_append = 0;