[newlib-cygwin] Fix gcvt to always show 'ndigits' of precision

[Corinna Vinschen <corinna@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=11f99384d2971356bab2fcac7e29792250abea73

commit 11f99384d2971356bab2fcac7e29792250abea73
Author: Keith Packard <keithp@keithp.com>
Date:   Wed Dec 18 08:49:06 2019 -0800

    Fix gcvt to always show 'ndigits' of precision
    
    Leading zeros after the decimal point should not count
    towards the 'ndigits' limit.
    
    This makes gcvt match glibc and the posix gcvt man page.
    
    Signed-off-by: Keith Packard <keithp@keithp.com>

Diff:
---
 newlib/libc/stdlib/ecvtbuf.c | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/newlib/libc/stdlib/ecvtbuf.c b/newlib/libc/stdlib/ecvtbuf.c
index 12e8c9a..228362e 100644
--- a/newlib/libc/stdlib/ecvtbuf.c
+++ b/newlib/libc/stdlib/ecvtbuf.c
@@ -349,15 +349,10 @@ _gcvt (struct _reent *ptr,
       char *end;
       char *p;
 
-      if (invalue < 1.0)
-	{
-	  /* what we want is ndigits after the point */
-	  p = _dtoa_r (ptr, invalue, 3, ndigit, &decpt, &sign, &end);
-	}
-      else
-	{
-	  p = _dtoa_r (ptr, invalue, 2, ndigit, &decpt, &sign, &end);
-	}
+      /* We always want ndigits of precision, even if that means printing
+       * a bunch of leading zeros for numbers < 1.0
+       */
+      p = _dtoa_r (ptr, invalue, 2, ndigit, &decpt, &sign, &end);
 
       if (decpt == 9999)
 	{
@@ -383,11 +378,12 @@ _gcvt (struct _reent *ptr,
 	  if (buf == save)
 	    *buf++ = '0';
 	  *buf++ = '.';
-	  while (decpt < 0 && ndigit > 0)
+
+	  /* Leading zeros don't count towards 'ndigit' */
+	  while (decpt < 0)
 	    {
 	      *buf++ = '0';
 	      decpt++;
-	      ndigit--;
 	    }
 
 	  /* Print rest of stuff */