[buildbot] phase1: parallelize target/install phase

[LEDE Commits]

jow pushed a commit to buildbot.git, branch master:
https://git.lede-project.org/5e9e04d357eed05e120f02d3a2cc379812b9331a

commit 5e9e04d357eed05e120f02d3a2cc379812b9331a
Author: Jo-Philipp Wich <jo at mein.io>
AuthorDate: Fri Nov 4 14:07:35 2016 +0100

    phase1: parallelize target/install phase
    
    Signed-off-by: Jo-Philipp Wich <jo at mein.io>
---
 phase1/master.cfg | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/phase1/master.cfg b/phase1/master.cfg
index 099f666..908087e 100644
--- a/phase1/master.cfg
+++ b/phase1/master.cfg
@@ -461,7 +461,7 @@ EOT''' %(ts[0], ts[0], ts[1]) ))
 	factory.addStep(ShellCommand(
 		name = "images",
 		description = "Building images",
-		command=["make", "-j1", "target/install", "V=s"],
+		command=["make", WithProperties("-j%(nproc:~4)s"), "target/install", "V=s"],
 		doStepIf = isChangeBuiltin,
 		haltOnFailure = True
 	))