MSVC AppVeyor random failures. Try to workaround.

AppVeyor reports issues like "fatal error C1041: cannot open program database"
randomly. The /FS flag is supposed to correct this on highly parallel builds
like performed when using Ninja, but it looks like CMake already adds this.
Maybe appending it at the end will work as maybe some prior flag is
counteracting its effectiveness.

Fix By: Brad House (@bradh352)

CMakeLists.txt

@@ -688,7 +688,6 @@ IF (HAVE_ARPA_NAMESER_COMPAT_H)
 	SET (CARES_HAVE_ARPA_NAMESER_COMPAT_H 1)
 ENDIF()
 
-
 # Coverage
 IF (CARES_COVERAGE)
 	# set compiler flags
@@ -709,6 +708,15 @@ IF (CARES_COVERAGE)
 	)
 ENDIF()
 
+IF (MSVC)
+	# AppVeyor reports issues like "fatal error C1041: cannot open program database" randomly.
+	# The /FS flag is supposed to correct this on highly parallel builds like performed when
+	# using Ninja, but it looks like CMake already adds this.  Maybe appending it at the
+	# end will work as maybe some prior flag is counteracting its effectiveness.
+	SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /FS")
+	SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /FS")
+ENDIF ()
+
 # TRANSFORM_MAKEFILE_INC
 #
 # This function consumes the "Makefile.inc" autotools file, and converts it into