Bug 1386739 - Only pass --output-sync=line to make in automation. r=gps

MozReview-Commit-ID: BN8nJv1wAr0

--HG--
extra : rebase_source : ab5ead968ec890fd4ad728f1282bbcb57742dfb8

client.mk

@@ -142,9 +142,11 @@ ifeq (,$(findstring -j,$(MOZ_MAKE_FLAGS)))
   MOZ_MAKE_FLAGS += -j$(cores)
 endif
 
+ifdef MOZ_AUTOMATION
 ifeq (4.0,$(firstword $(sort 4.0 $(MAKE_VERSION))))
 MOZ_MAKE_FLAGS += --output-sync=line
 endif
+endif
 
 ifdef MOZ_BUILD_PROJECTS