Fix a nasty bug that was closing stdin

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3663 42af7a65-404d-4744-a932-0658087f49c3

lib/stdio/lib_fgets.c

@@ -97,7 +97,10 @@ static const char g_erasetoeol[] = "\033[K";
 static inline int _lib_rawgetc(int fd)
 {
   char buffer;
-  if (read(fd, &buffer, 1) < 1)
+  ssize_t nread;
+
+  nread = read(fd, &buffer, 1);
+  if (nread < 1)
     {
       /* Return EOF if the end of file (0) or error (-1) occurs */