lib/src/: a2i_strto[iu](): Support other errno values

An implementation of strto[iu]max(3) may choose to fail with for example
ENOMEM.  Behave well with those.

The reason for the weird indentation is to reduce the diff in the
following patch.

Reported-by: Bruno Haible <bruno@clisp.org>
Signed-off-by: Alejandro Colomar <alx@kernel.org>

lib/src/a2i/strtoi/strtoi/strtoi.h

diff --git a/lib/src/a2i/strtoi/strtoi/strtoi.h b/lib/src/a2i/strtoi/strtoi/strtoi.h
index 900b2eb..cc76700 100644
--- a/lib/src/a2i/strtoi/strtoi/strtoi.h
+++ b/lib/src/a2i/strtoi/strtoi/strtoi.h
@@ -53,9 +53,12 @@
 
 	if (e == NULL)
 		st = errno;
+	else
+	if (errno != 0 && errno != EINVAL)
+		st = errno;
 	else if (e == s)
 		st = ECANCELED;
-	else if (errno == ERANGE || n < min || n > max)
+	else if (n < min || n > max)
 		st = ERANGE;
 	else if (*e != '\0')
 		st = ENOTSUP;

lib/src/a2i/strtoi/strtou/strtou.h

diff --git a/lib/src/a2i/strtoi/strtou/strtou.h b/lib/src/a2i/strtoi/strtou/strtou.h
index cfb0e45..a7761ed 100644
--- a/lib/src/a2i/strtoi/strtou/strtou.h
+++ b/lib/src/a2i/strtoi/strtou/strtou.h
@@ -53,9 +53,12 @@
 
 	if (e == NULL)
 		st = errno;
+	else
+	if (errno != 0 && errno != EINVAL)
+		st = errno;
 	else if (e == s)
 		st = ECANCELED;
-	else if (errno == ERANGE || n < min || n > max)
+	else if (n < min || n > max)
 		st = ERANGE;
 	else if (*e != '\0')
 		st = ENOTSUP;