windows build: ignore utf-8 decode errors when acquiring vs envvars

Change-Id: Id4c8b662a6e10d65bb106cf5ff917f97c8ff4089

make-lrc.py

@@ -73,7 +73,7 @@ def getVSEnv(arch='x64', platform='', version=''):
                          shell=True,
                          stdout=subprocess.PIPE)
     stdout, _ = p.communicate()
-    out = stdout.decode('utf-8').split("\r\n")[5:-1]
+    out = stdout.decode('utf-8', 'ignore').split("\r\n")[5:-1]
     return dict(s.split('=', 1) for s in out)