[PATCH] [ASan tests] Add Windows-specific flags to lib/asan/tests/CMakeLists.txt

[Timur Iskhodzhanov]

Landed everything except for one questionable if() in r208682.

================
Comment at: lib/asan/tests/CMakeLists.txt:77
@@ -50,2 +76,3 @@
 # Unit tests require libstdc++.
-set(ASAN_UNITTEST_COMMON_LINKFLAGS -lstdc++)
+if(NOT MSVC)
+  set(ASAN_UNITTEST_COMMON_LINKFLAGS -lstdc++)
----------------
Alexey Samsonov wrote:
> Why do you need this? If there is no libstdc++ on Windows, you should instead detect this in the build system and introduce
> COMPILER_RT_HAS_LIBSTDCXX like we do for libpthread and libdl.
We had an offline discussion here and wonder why doesn't the driver itself pass this flag?

We also have to do `if(NOT MSVC)` for the recently-introduced `--driver=g++` flag here anyways, so not clear if the extra variable is worth it.

(we can probably discuss that on the commit email)

http://reviews.llvm.org/D3720