fix error when use xcode 8 to build luajit lib for ios
fix error when use xcode 8 to build luajit lib for ios

set development target to 8.0 on gcc to fix the error "ld: library not found for -lcrt1.3.1.o" when compile into armv7 and armv7s using XCode 8
haolly/slua_source_note,jiangzhhhh/slua,pangweiwei/slua,haolly/slua_source_note,mr-kelly/slua,soulgame/slua,Roland0511/slua,Roland0511/slua,jiangzhhhh/slua,soulgame/slua,pangweiwei/slua,soulgame/slua,Roland0511/slua,jiangzhhhh/slua,mr-kelly/slua,jiangzhhhh/slua,pangweiwei/slua,mr-kelly/slua,soulgame/slua,haolly/slua_source_note,Roland0511/slua,haolly/slua_source_note,Roland0511/slua,mr-kelly/slua,soulgame/slua,pangweiwei/slua,pangweiwei/slua,jiangzhhhh/slua,jiangzhhhh/slua,haolly/slua_source_note,mr-kelly/slua,soulgame/slua,mr-kelly/slua,haolly/slua_source_note,Roland0511/slua