Fix windows exception handling in build

[srajko]

Even though we had the /EHsc option in the gyp file, it was not being applied correctly. With the change, the option does get applied, which also takes care of numerous build warnings like this one:

C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\xtree(839): warning C4530: C++ exception handler used, but unwind semantics are not enabled. Specify /EHsc (..\src\lock_master.cc) [C:\projects\nodegit\build\nodegit.vcxproj]

[saper]

You can use ExceptionHandling: Sync in gyp to indicate /EHsc

[srajko]

@saper thanks for the tip, that would be cleaner but it looks like it still results in warnings for node 0.12 builds. You can compare https://ci.appveyor.com/project/TimBranyen/nodegit/build/3029 (using "ExceptionHandling": "Sync") and https://ci.appveyor.com/project/TimBranyen/nodegit/build/3031 (using "AdditionalOptions": [ "/EHsc" ]).

Maybe when we drop node 0.12?

[saper]

My mistake. The parameter should be integer, I think the value of one(1) should do it.

[saper]

/FORCE:MULTIPLE also has its gyp equivalent, ForceFileOutput.

[srajko]

I am getting the same results with "ExceptionHandling": 1 as with "ExceptionHandling": "Sync" - the /EHsc warnings disappear for node 4, 5, and 6, but remain for 0.12. This is the build output for "ExceptionHandling": 1: https://ci.appveyor.com/project/TimBranyen/nodegit/build/3032

So both 1 and Sync have an effect for node >0.12 but not 0.12. See in contrast the build output for an unrelated PR, where the /EHsc warnings appear for all versions of node: https://ci.appveyor.com/project/TimBranyen/nodegit/build/3030

[saper]

Strange, it should not depend on the node version. I'll check when I get somewhere near Windows. In the meantime go ahead with your changes. I just figured out at node-sass we are also using /EHsc literally.