Disable C++ exceptions in std libraries on Windows

Disable C++ exceptions in std libraries on Windows

As Dart C++ code cannot use C++ exceptions make sure that the C++ libraries on Windows does not try to use C++ exceptions.

This gets rid of the warning

  warning C4530: C++ exception handler used, but unwind semantics are not enabled. Specify /EHsc

when compiling on Windows.

R=iposva@google.com

Committed: https://code.google.com/p/dart/source/detail?r=10167

[Søren Gjesse, 2012-08-02 13:30:30]

Moved setting to MSVC configuration file.

[Mads Ager (google), 2012-08-02 13:32:04]

lgtm