stdio: lib_fgets convert \r\n to \n

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>

libs/libc/stdio/lib_libfgets.c

@@ -142,6 +142,13 @@ FAR char *lib_fgets(FAR char *buf, size_t buflen, FILE *stream,
 
       if (ch == '\n')
         {
+          /* Convert \r\n to \n */
+
+          if (nch > 0 && buf[nch - 1] == '\r')
+            {
+              --nch;
+            }
+
           if (keepnl)
             {
               /* Store newline is stored in the buffer */
@@ -161,7 +168,7 @@ FAR char *lib_fgets(FAR char *buf, size_t buflen, FILE *stream,
         {
           /* End of file with no data? */
 
-          if (!nch)
+          if (nch == 0)
             {
               /* Yes.. return NULL as the end of file mark */