Escaping in PACKAGECONFIG

[Boszormenyi Zoltan <zboszor@pr.hu>]

Hi,

what is the proper way of escaping a comma in the string specified for PACKAGECONFIG?
I would like to use something like the below in my custom PHP recipe:

PACKAGECONFIG[mysql] = ' \
                        --enable-mysqlnd="shared" \
                        --with-mysql="shared,mysqlnd" \
                        --with-mysqli="shared,mysqlnd" \
                        --with-mysql-sock=${localstatedir}/lib/mysql/mysql.sock \
                        --with-pdo-mysql="shared,mysqlnd" \
                        , \
                        ,mysql5'

With ...="shared,mysqlnd", ...="shared\,mysqlnd" or ...="shared\\,mysqlnd" I get:

ERROR: Only enable,disable,depend,rdepend can be specified!

and

ERROR: Nothing PROVIDES 'mysqlnd"' (but .../php/php_5.6.3.bb DEPENDS on or otherwise
requires it). Close matches:
  mysql5
ERROR: Required build target 'php' has no buildable providers.
Missing or unbuildable dependency chain was: ['php', 'mysqlnd"']

But, this works:

MYSQLND="shared,mysqlnd"
PACKAGECONFIG[mysql] = ' \
                        --enable-mysqlnd="shared" \
                        --with-mysql=${MYSQLND} \        
                        --with-mysqli=${MYSQLND} \                 
                        --with-mysql-sock=${localstatedir}/lib/mysql/mysql.sock \
                        --with-pdo-mysql=${MYSQLND} \                 
                        , \
                        ,mysql5'

Why?

Thanks in advance,
Zoltán Böszörményi