libcroco: disable Bsymbolic if it is not supported on some hosts

libcroco: disable Bsymbolic if it is not supported on some hosts

When trying to build on my Centos 5.5 machine, got below error:
| checking for gtkdoc-mkpdf... no
| checking whether to build gtk-doc documentation... no
| checking for CROCO... yes
| checking if gcc supports "-Wl,-Bsymbolic-functions" flag...
| configure: error: -Bsymbolic requested but not supported by ld. Use --disable-Bsymbolic to disable
| Configure failed. The contents of all config.log files follows to aid debugging
|
| configure: exit 1
| ERROR: oe_runconf failed

Set --enable-Bsymbolic=auto to disable it when it is not suppported.

(From OE-Core rev: e7c691b33573b3309752d6eb397486c2c8620adb)

Signed-off-by: Ting Liu <b28495@freescale.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>