MC clobbers the PROMPT_COMMAND shell variable [http://www.midnight-commander.org/ticket/2027]

subshell_prompt.patch

diff -udpr src/subshell.c.orig src/subshell.c
--- src/subshell.c.orig	2013-08-02 18:02:39.000000000 +0300
+++ src/subshell.c	2013-10-28 10:47:34.000000000 +0200
@@ -769,7 +769,7 @@ init_subshell (void)
 {
     /* This must be remembered across calls to init_subshell() */
     static char pty_name[BUF_SMALL];
-    char precmd[BUF_SMALL];
+    char precmd[BUF_MEDIUM];

     switch (check_sid ())
     {
@@ -884,7 +884,7 @@ init_subshell (void)
     {
     case BASH:
         g_snprintf (precmd, sizeof (precmd),
-                    " PROMPT_COMMAND='pwd>&%d;kill -STOP $$'\n", subshell_pipe[WRITE]);
+		    " PROMPT_COMMAND=${PROMPT_COMMAND:+$PROMPT_COMMAND; }'pwd>&%d;kill -STOP $$'\n", subshell_pipe[WRITE]);
         break;

     case ZSH: