local-conf: enable bitbake parallel builds

On build machines with multiple cores, bitbake can execute build
tasks in parallel.  These defaults should be modified to match the
number of cores on the build machine.

OXT-1736

Signed-off-by: Rich Persaud <rich.persaud@baesystems.com>

build/conf/local.conf-dist

@@ -1,5 +1,9 @@
 CONF_VERSION = "1"
 
+# Enable parallel builds on multi-core machines
+BB_NUMBER_THREADS ?= "4"
+PARALLEL_MAKE ?= "-j 4"
+
 # 1) Basic config
 #
 ## TODO: DISTRO should be in auto.conf