windows: Disable Runtime checks

Runtime checks are asserting on the embedded ZLib code because of
truncation (see zlib/trees.c:218). This is not good or pretty, but I'm
wary about patching the ZLib code even more.

There are two ways to fix this:

	- Patch the ZLib code, and start storing a diff/patchset on
	how does our version of ZLib differ from the original one, so we can
	be more or less on sync when new version of ZLib.

	- Go back to ZLib as an external dependency, which is np for *NIX
	users but annoying as dicks for Windows users.

THINK HARD

CMakeLists.txt

@@ -37,7 +37,8 @@ OPTION (THREADSAFE "Build libgit2 as threadsafe" OFF)
 # Platform specific compilation flags
 IF (MSVC)
 	SET(CMAKE_C_FLAGS "/TC /W4 /WX /nologo /Zi")
-	SET(CMAKE_C_FLAGS_DEBUG "/Od /RTC1 /RTCc /DEBUG /MTd")
+	# TODO: bring back /RTC1 /RTCc
+	SET(CMAKE_C_FLAGS_DEBUG "/Od /DEBUG /MTd")
 	SET(CMAKE_C_FLAGS_RELEASE "/MT /O2")
 ENDIF()