fs_shell: Adjust to work with the new libroot_build errno setup.

I rebuilt fs_shell after the previous commit before pushing,
but it didn't fail then. I guess Jam failed to do an incremental
rebuild properly...

headers/private/fs_shell/fssh_errno.h

@@ -11,8 +11,8 @@ extern "C"
 #define FSSH_ENOERR          0
 #define FSSH_EOK 			FSSH_ENOERR  /* some code assumes EOK exists */
 
-extern int *_fssh_errnop(void);
-#define fssh_errno (*(_fssh_errnop()))
+extern int _fssh_errno(void);
+#define fssh_errno (_fssh_errno())
 
 extern int	fssh_get_errno(void);
 extern void	fssh_set_errno(int error);

src/tools/fs_shell/errno.cpp

@@ -10,10 +10,10 @@
 #include <errno.h>
 
 
-int *
-_fssh_errnop(void)
+int
+_fssh_errno(void)
 {
-	return &errno;
+	return errno;
 }