Flush all streams at exit

This is a general version of commit d551f3. And I expect this will
replace commit 5e8528 and 13c1e9, too.

    modified:   builtin/credential-store.c
    modified:   compat/os2.c
    modified:   run-command.c

builtin/credential-store.c

@@ -52,11 +52,6 @@ static void print_entry(struct credential *c)
 {
 	printf("username=%s\n", c->username);
 	printf("password=%s\n", c->password);
-	/*
-	 * OS/2 kLIBC requires to flush a stream explicitly when it is a socket.
-	 * Otherwise, buffered outputs are lost.
-	 */
-	fflush(stdout);
 }
 
 static void print_line(struct strbuf *buf)

compat/os2.c

@@ -1729,6 +1729,15 @@ static char *toutf8dup(const char *in)
 	return realloc(out, strlen(out) + 1);
 }
 
+static void flush( void )
+{
+  /*
+   * OS/2 kLIBC requires to flush a stream explicitly when it is a socket.
+   * Otherwise, buffered outputs are lost.
+   */
+  fflush(NULL);
+}
+
 int git_os2_main_prepare (int * p_argc, char ** * p_argv)
 {
   _control87(MCW_EM, MCW_EM); /* mask all FPEs */
@@ -1808,6 +1817,12 @@ int git_os2_main_prepare (int * p_argc, char ** * p_argv)
    */
    putenv("PERLIO=perlio");
 
+  /*
+   * Flush all streams at exit. This prevents buffered outputs from being lost,
+   * especially in case of a stream fdopen()ed from a socket.
+   */
+  atexit(flush);
+
 #ifdef i_need_debug_output
   {
   extern const char *system_path(const char *path);

run-command.c

@@ -983,22 +983,6 @@ int start_command(struct child_process *cmd)
 	else if (cmd->in)
 		close(cmd->in);
 
-#ifdef __OS2__
-	/*
-	 * When socketpair() is used as a back-end for pipe(), reading from
-	 * cmd->out does not wait for it to be filled even if it is in
-	 * blocking-mode if fdout[1] is closed. So, wait here instead before
-	 * closing fdout[1].
-	 */
-	if (need_out && cmd->git_cmd) {
-		struct pollfd pollfd;
-
-		pollfd.fd = cmd->out;
-		pollfd.events = POLLIN;
-		poll(&pollfd, 1, 1500); /* up to 1.5s at most */
-	}
-#endif
-
 	if (need_out)
 		close(fdout[1]);
 	else if (cmd->out)