bind: disable parallel build

The build system of bind seems to have issues with (highly) parallel
builds, breaking the build with errors like:

libtool: link: `nothreads/condition.lo' is not a valid libtool object

So disable parallel builds.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/bind/bind.mk

@@ -11,6 +11,7 @@ BIND_TARGET_SBINS += named-compilezone rndc rndc-confgen
 BIND_TARGET_SBINS += dnssec-keygen dnssec-signzone
 BIND_TARGET_BINS = dig host nslookup nsupdate
 BIND_TARGET_LIBS = libbind9.* libdns.* libisccc.* libisccfg.* libisc.* liblwres.*
+BIND_MAKE = $(MAKE1)
 BIND_CONF_ENV =	BUILD_CC="$(TARGET_CC)" \
 		BUILD_CFLAGS="$(TARGET_CFLAGS)"
 BIND_CONF_OPT =	\