[newlib-cygwin] Print sign of NaN values to nano-vfprintf.

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=6d7e0b337c16421a460ab0594db67bdecb377c67

commit 6d7e0b337c16421a460ab0594db67bdecb377c67
Author: Kumar Gala <kumar.gala@linaro.org>
Date:   Thu Jul 12 13:13:53 2018 -0500

    Print sign of NaN values to nano-vfprintf.
    
    Signed-off-by: Kumar Gala <kumar.gala@linaro.org>

Diff:
---
 newlib/libc/stdio/nano-vfprintf_float.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/newlib/libc/stdio/nano-vfprintf_float.c b/newlib/libc/stdio/nano-vfprintf_float.c
index 98893e9..071a09e 100644
--- a/newlib/libc/stdio/nano-vfprintf_float.c
+++ b/newlib/libc/stdio/nano-vfprintf_float.c
@@ -213,6 +213,8 @@ _printf_float (struct _reent *data,
     }
   if (isnan (_fpvalue))
     {
+      if (_fpvalue < 0)
+	pdata->l_buf[0] = '-';
       if (code <= 'G')		/* 'A', 'E', 'F', or 'G'.  */
 	cp = "NAN";
       else