CMake: Reduce warnings in MSVC build.

In the MSVC build, `-Wall` isn't as useful as it includes warnings
about padding in structs which is quite spammy.

mindy/CMakeLists.txt

@@ -18,6 +18,10 @@ ENDIF()
 
 OPTION(MINDY_USE_SIGNALS "Use signals." ${MINDY_USE_SIGNALS})
 
+IF(MSVC)
+  ADD_DEFINITIONS(-D_CRT_SECURE_NO_WARNINGS)
+ENDIF()
+
 CHECK_FUNCTION_EXISTS(_setjmp HAVE__SETJMP)
 CHECK_FUNCTION_EXISTS(_longjmp HAVE__LONGJMP)
 
@@ -90,7 +94,9 @@ ENDIF()
 
 ADD_DEFINITIONS(-DLIBDIR="${CMAKE_INSTALL_PREFIX}/${MINDY_LIB_DIR}")
 
-ADD_C_COMPILER_FLAG(-Wall)
+IF(NOT MSVC)
+  ADD_C_COMPILER_FLAG(-Wall)
+ENDIF()
 
 # clang doesn't print colored diagnostics when invoked from Ninja
 IF (UNIX AND