cmake HAVE_RESOLV examples

baresip/re cmake/re-config.cmake :60 

check_symbol_exists(res_init resolv.h HAVE_RESOLV)

baresip/re cmake/re-config.cmake :62 

check_symbol_exists(res_ninit resolv.h HAVE_RESOLV)

baresip/re cmake/re-config.cmake :65 

list(APPEND RE_DEFINITIONS HAVE_RESOLV)

baresip/re cmake/re-config.cmake :67 

elseif(HAVE_RESOLV)

baresip/re cmake/re-config.cmake :69 

list(APPEND RE_DEFINITIONS HAVE_RESOLV)