teach gdtoa & its subroutines that malloc can fail; in which case

ecvt, fcvt, gcvt, *printf, strtof, strtod, strtold act per ieee
1003.1.  after these massive changes, remove unused files which
would not work now.  reported by Maksymilian Arciemowicz;  ok theo

src/lib/libc/stdlib/ecvt.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: ecvt.c,v 1.6 2006/10/29 18:45:56 deraadt Exp $	*/
+/*	$OpenBSD: ecvt.c,v 1.7 2009/10/16 12:15:03 martynas Exp $	*/
 
 /*
  * Copyright (c) 2002, 2006 Todd C. Miller <Todd.Miller@courtesan.com>
@@ -62,6 +62,8 @@ __cvt(double value, int ndigit, int *decpt, int *sign, int fmode, int pad)
 		*rve = '\0';
 	} else {
 		p = __dtoa(value, fmode + 2, ndigit, decpt, sign, &rve);
+		if (p == NULL)
+			return (NULL);
 		if (*decpt == 9999) {
 			/* Infinity or Nan, convert to inf or nan like printf */
 			*decpt = 0;

src/lib/libc/stdlib/gcvt.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: gcvt.c,v 1.10 2006/10/29 18:45:56 deraadt Exp $	*/
+/*	$OpenBSD: gcvt.c,v 1.11 2009/10/16 12:15:03 martynas Exp $	*/
 
 /*
  * Copyright (c) 2002, 2003, 2006 Todd C. Miller <Todd.Miller@courtesan.com>
@@ -42,6 +42,8 @@ gcvt(double value, int ndigit, char *buf)
 	}
 
 	digits = __dtoa(value, 2, ndigit, &decpt, &sign, NULL);
+	if (digits == NULL)
+		return (NULL);
 	if (decpt == 9999) {
 		/*
 		 * Infinity or NaN, convert to inf or nan with sign.