libvncserver: fix build without pthread

Fixes http://autobuild.buildroot.net/results/761/7618028d0781269d2f6f0a14d814da456f207475/

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libvncserver/libvncserver.mk

@@ -15,6 +15,10 @@ LIBVNCSERVER_CONFIG_SCRIPTS = libvncserver-config
 # only used for examples
 LIBVNCSERVER_CONF_OPT += --with-sdl-config=/bin/false
 
+ifneq ($(BR2_TOOLCHAIN_HAS_THREADS),y)
+LIBVNCSERVER_CONF_OPT += --without-pthread
+endif
+
 ifneq ($(BR2_INET_IPV6),y)
 LIBVNCSERVER_CONF_OPT += --without-ipv6
 endif