Fix CMake build flags for MinGW
Fix CMake build flags for MinGW

liu3tao/jansson,liu3tao/jansson,npmccallum/jansson,wirebirdlabs/featherweight-jansson,AmesianX/jansson,chrullrich/jansson,markalanj/jansson,bstarynk/jansson,slackner/jansson,akheron/jansson,Vorne/jansson,Vorne/jansson,akheron/jansson,bstarynk/jansson,npmccallum/jansson,firepick1/jansson,bstarynk/jansson,firepick1/jansson,AmesianX/jansson,markalanj/jansson,Mephistophiles/jansson,firepick1/jansson,markalanj/jansson,chrullrich/jansson,Mephistophiles/jansson,akheron/jansson,OlehKulykov/jansson,OlehKulykov/jansson,wirebirdlabs/featherweight-jansson,slackner/jansson