util-linux: Fix floating dependency upon 'readline'

The configure script checks for 'readline' availability and enables
it, if available. Now, a PACKAGECONFIG (readline) controls the
feature.

(From OE-Core rev: 574b84132df61d421d2f99e14bdc94649fe83e38)

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-core/util-linux/util-linux.inc

@@ -61,6 +61,9 @@ PACKAGECONFIG[libcap-ng] = "--enable-setpriv,--disable-setpriv,libcap-ng,"
 # Build python bindings for libmount
 PACKAGECONFIG[pylibmount] = "--with-python --enable-pylibmount,--without-python --disable-pylibmount,python"
 
+# Readline support
+PACKAGECONFIG[readline] = "--with-readline,--without-readline,readline"
+
 FILES_${PN}-bash-completion += "${datadir}/bash-completion"
 FILES_${PN}-doc += "${datadir}/getopt/getopt-*.*"