Use realine instead of fgets in several other places

git-svn-id: https://nuttx.svn.sourceforge.net/svnroot/nuttx/trunk@4357 7fd9a85b-ad96-42d3-883c-3090e2eb8679

apps/nshlib/README.txt

@@ -1047,3 +1047,11 @@ Common Problems
     Make sure that the polled console is disabled in the OS configuration
     file, .config.  That file should have CONFIG_DEV_LOWCONSOLE=n for
     NSH over serial.
+
+  Problem:
+    The function 'readline' is undefined.
+  Usual Cause:
+    The following is missing from your appconfig file:
+
+    CONFIGURED_APPS += system/readline
+

apps/nshlib/nsh_serial.c

@@ -525,7 +525,7 @@ int nsh_consolemain(int argc, char *argv[])
 
       else
         {
-          fprintf(pstate->ss_outstream, g_fmtcmdfailed, "readline", NSH_ERRNO);
+          fprintf(pstate->ss_outstream, g_fmtcmdfailed, "readline", NSH_ERRNO_OF(-ret));
           return 1;
         }
     }