CE Implement line editing

ce/interp.c

@@ -6,6 +6,7 @@
 #include <desc.h>
 #include <filereader.h>
 #include <filewriter.h>
+#include <kb.h>
 #include <path.h>
 #include <process.h>
 #include <stddef.h>
@@ -13,8 +14,6 @@
 #include <string.h>
 #include <system.h>
 
-#define CTRL(x) ((x) - '@')
-
 static bool run = true;
 
 bool interp_is_running (void) { return run; }
@@ -164,7 +163,7 @@ static void cmd_cancel_proc (void) {
   for (;;) {
     mail_receive (&ch, 1);
 
-    if (ch == CTRL ('C'))
+    if (ch == KB_CTRL ('C'))
       break;
   }