Run gyp with --no-parallel -G config=$(BUILDTYPE)

BUG=skia:3287

Review URL: https://codereview.chromium.org/972943003
diff --git a/Makefile b/Makefile
index baaabfa..25a46cc 100644
--- a/Makefile
+++ b/Makefile
@@ -86,7 +86,7 @@
 # Run gyp no matter what.
 .PHONY: gyp
 gyp:
-	$(CWD)/gyp_skia
+	$(CWD)/gyp_skia --no-parallel -G config=$(BUILDTYPE)
 
 # For all specific targets: run gyp if necessary, and then pass control to
 # the gyp-generated buildfiles.