sudo: Fix case where ${B} != ${S}

Fix out of tree builds by using full path to files in ${S} and remove
cwd assumptions.

(From OE-Core rev: 97dc39e42e95dcadc7bed1aee32db3560e21efe5)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-extended/sudo/sudo.inc

@@ -16,8 +16,8 @@ inherit autotools
 EXTRA_OECONF = "--with-editor=/bin/vi --with-env-editor"
 
 do_configure_prepend () {
-	if [ ! -e acinclude.m4 ]; then
-		cat aclocal.m4 > acinclude.m4
+	if [ ! -e ${S}/acinclude.m4 ]; then
+		cat ${S}/aclocal.m4 > ${S}/acinclude.m4
 	fi
 }