sox: disable ssp when unavailable

It seems autodetection isn't good. Fixes:
http://autobuild.buildroot.net/results/885/885c7daec7b727d8a7cf47c7576f0e79d4a5ddf8/

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/sox/sox.mk

@@ -8,7 +8,8 @@ SOX_VERSION = 14.4.2
 SOX_SITE = http://downloads.sourceforge.net/project/sox/sox/$(SOX_VERSION)
 SOX_SOURCE = sox-$(SOX_VERSION).tar.bz2
 SOX_DEPENDENCIES = host-pkgconf
-SOX_CONF_OPTS = --with-distro="Buildroot" --without-ffmpeg --disable-gomp
+SOX_CONF_OPTS = --with-distro="Buildroot" --without-ffmpeg --disable-gomp \
+	$(if $(BR2_TOOLCHAIN_HAS_SSP),,--disable-stack-protector)
 SOX_LICENSE = GPLv2+ (sox binary), LGPLv2.1+ (libraries)
 SOX_LICENSE_FILES = LICENSE.GPL LICENSE.LGPL