[newlib-cygwin] strtold: set errno to ERANGE on underflow per POSIX

[Corinna Vinschen <corinna@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=c81a76b3b96a7e4b12e13d73ef4834142852213b

commit c81a76b3b96a7e4b12e13d73ef4834142852213b
Author: Bruno Haible <bruno@clisp.org>
Date:   Mon Dec 16 15:11:47 2019 +0100

    strtold: set errno to ERANGE on underflow per POSIX
    
    https://pubs.opengroup.org/onlinepubs/9699919799/functions/strtod.html

Diff:
---
 newlib/libc/stdlib/strtodg.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/newlib/libc/stdlib/strtodg.c b/newlib/libc/stdlib/strtodg.c
index 0133159..743f60b 100644
--- a/newlib/libc/stdlib/strtodg.c
+++ b/newlib/libc/stdlib/strtodg.c
@@ -348,6 +348,9 @@ rvOK (struct _reent *p, double d, FPI *fpi, Long *exp, __ULong *bits, int exact,
 		if (k > nb || fpi->sudden_underflow) {
 			b->_wds = inex = 0;
 			*irv = STRTOG_Underflow | STRTOG_Inexlo;
+#ifndef NO_ERRNO
+			errno = ERANGE;
+#endif
 			}
 		else {
 			k1 = k - 1;
@@ -362,9 +365,15 @@ rvOK (struct _reent *p, double d, FPI *fpi, Long *exp, __ULong *bits, int exact,
 			if (carry) {
 				b = increment(p, b);
 				inex = STRTOG_Inexhi | STRTOG_Underflow;
+#ifndef NO_ERRNO
+				errno = ERANGE;
+#endif
 				}
 			else if (lostbits)
 				inex = STRTOG_Inexlo | STRTOG_Underflow;
+#ifndef NO_ERRNO
+				errno = ERANGE;
+#endif
 			}
 		}
 	else if (e > fpi->emax) {
@@ -761,6 +770,9 @@ _strtodg_l (struct _reent *p, const char *s00, char **se, FPI *fpi, Long *exp,
 					rvb->_x[0] = 0;
 					*exp = emin;
 					irv = STRTOG_Underflow | STRTOG_Inexlo;
+#ifndef NO_ERRNO
+					errno = ERANGE;
+#endif
 					goto ret;
 					}
 				rvb->_x[0] = rvb->_wds = rvbits = 1;
@@ -940,6 +952,9 @@ _strtodg_l (struct _reent *p, const char *s00, char **se, FPI *fpi, Long *exp,
 				rvb->_wds = 0;
 				rve = emin;
 				irv = STRTOG_Underflow | STRTOG_Inexlo;
+#ifndef NO_ERRNO
+				errno = ERANGE;
+#endif
 				break;
 				}
 			adj0 = dval(adj) = 1.;
@@ -1083,12 +1098,18 @@ _strtodg_l (struct _reent *p, const char *s00, char **se, FPI *fpi, Long *exp,
 		if (sudden_underflow) {
 			rvb->_wds = 0;
 			irv = STRTOG_Underflow | STRTOG_Inexlo;
+#ifndef NO_ERRNO
+			errno = ERANGE;
+#endif
 			}
 		else  {
 			irv = (irv & ~STRTOG_Retmask) |
 				(rvb->_wds > 0 ? STRTOG_Denormal : STRTOG_Zero);
 			if (irv & STRTOG_Inexact)
 				irv |= STRTOG_Underflow;
+#ifndef NO_ERRNO
+				errno = ERANGE;
+#endif
 			}
 		}
 	if (se)