[Piglit] [PATCH] core.py: don't overwrite user's PIGLIT_SOURCE_DIR env var

[Brian Paul]

When creating an Options object, use the environment's PIGLIT_SOURCE_DIR
value when available.

Fixes spec/ARB_ES3_compatibility/oes_compressed_etc2_texture-miptree test
failures in Cywin.

Also, remove the MESA_DEBUG=silent setting.  Piglit shouldn't care if
debug output is on/off (we stopped looking for Mesa error messages a
long time ago).

v2: simplify code with dict get() method and default value.
---
 framework/core.py |    7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/framework/core.py b/framework/core.py
index f7d6f71..c265e24 100644
--- a/framework/core.py
+++ b/framework/core.py
@@ -107,11 +107,10 @@ class Options(object):
         self.sync = sync
         # env is used to set some base environment variables that are not going
         # to change across runs, without sending them to os.environ which is
-        # fickle as easy to break
+        # fickle and easy to break
         self.env = {
-            'PIGLIT_SOURCE_DIR': os.path.abspath(
-                os.path.join(os.path.dirname(__file__), '..')),
-            'MESA_DEBUG': 'silent',
+            'PIGLIT_SOURCE_DIR': os.environ.get('PIGLIT_SOURCE_DIR',
+                 os.path.abspath(os.path.join(os.path.dirname(__file__), '..')))
         }
 
     def __iter__(self):
-- 
1.7.10.4