lib/49640: Improve example of strto[iu](3)

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>Number:         49640
>Category:       lib
>Synopsis:       Improve example of strto[iu](3)
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    lib-bug-people
>State:          open
>Class:          doc-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Feb 04 23:20:00 +0000 2015
>Originator:     Kamil Rytarowski
>Release:        current
>Organization:
>Environment:
N/A
>Description:
In the example usage of strtoi(3) and strtou(3) there is reused warn(3), which takes a value of errno. errno for the string conversion calls is guaranteed to be unchanged so warn(3) prints trash.
>How-To-Repeat:
man strtoi
man strtou
>Fix:
diff --git a/libc/stdlib/strtol.3 b/libc/stdlib/strtol.3
index 5eb586b..a1f3834 100644
--- a/libc/stdlib/strtol.3
+++ b/libc/stdlib/strtol.3
@@ -243,8 +243,8 @@ function is the simplest to use:
 int e;
 intmax_t lval = strtoi(buf, NULL, 0, 1, 99, &e);
 if (e)
-	warn("conversion of `%s' to a number failed, using %jd",
-	    buf, lval);
+	warnx("conversion of `%s' to a number failed, using %jd: %s",
+	    buf, lval, strerror(3));
 .Ed
 .Pp
 This will always return a number in
diff --git a/libc/stdlib/strtoul.3 b/libc/stdlib/strtoul.3
index ee0ebde..d3a59fa 100644
--- a/libc/stdlib/strtoul.3
+++ b/libc/stdlib/strtoul.3
@@ -240,8 +240,8 @@ function is the simplest to use:
 int e;
 uintmax_t lval = strtou(buf, NULL, 0, 1, 99, &e);
 if (e)
-	warn("conversion of `%s' to a number failed, using %ju",
-	    buf, lval);
+	warnx("conversion of `%s' to a number failed, using %ju: %s",
+	    buf, lval, strerror(e));
 .Ed
 .Pp
 This will always return a number in