Fix make.py: BUILDTYPE

TBR=mtklein
BUG=skia:
NOTRY=true
NOTREECHECKS=true

Review URL: https://codereview.chromium.org/1273793003 .
diff --git a/make.py b/make.py
index fcf81b5..d7bda84 100644
--- a/make.py
+++ b/make.py
@@ -17,7 +17,7 @@
 import shutil

 import sys

 

-BUILDTYPE = 'Debug'

+BUILDTYPE = os.environ.get('BUILDTYPE', 'Debug')

 

 # special targets

 TARGET_ALL     = 'all'