[PATCH] [zorg] Add options allowing MSVC builds with Clang Cmake Build Factory.

[Galina]

Thanks for working on this!

What is the use case for merging env on a slave?

================
Comment at: zorg/buildbot/builders/ClangBuilder.py:537
@@ -509,10 +536,3 @@
 
-    ############# CLEANING
-    if clean:
-        f.addStep(ShellCommand(name='clean stage 1',
-                               command=['rm','-rf',stage1_build],
-                               warnOnFailure=True,
-                               description='cleaning stage 1',
-                               descriptionDone='clean',
-                               workdir='.',
-                               env=env))
+    # Project file created by previous cmake run.
+    if 'Ninja' in cmakeGenerator:
----------------
Could you consider defining and using a dict instead? Seems more natural for Python...

================
Comment at: zorg/buildbot/builders/ClangBuilder.py:548
@@ +547,3 @@
+    ############# CLEANING
+    doCleanIf = lambda step: step.build.getProperty("force_build_clean") or clean
+    f.addStep(RemoveDirectory(name='clean stage 1',
----------------
May I suggest defining the "clean" arg as a property and then do a unified check if we need to clean.
The build property will overwrite the builder or a slave one.

At least this is what I'm going to do as a common approach for all builders.

http://reviews.llvm.org/D5588