fix pthread invoke on Android
fix pthread invoke on Android

mihailim/koreader,houqp/koreader,poire-z/koreader,Markismus/koreader,robert00s/koreader,NickSavage/koreader,Hzj-jie/koreader,NiLuJe/koreader,chihyang/koreader,lgeek/koreader,pazos/koreader,NiLuJe/koreader,apletnev/koreader,koreader/koreader,Frenzie/koreader,Frenzie/koreader,mwoz123/koreader,frankyifei/koreader,poire-z/koreader,koreader/koreader