1. build c-ares-1.5.2
./configure --prefix=/usr/local/
make;
make install

2. build curl-7.18.1
./configure --enable-ares=/usr/local --prefix=/usr/local
make;
make install

error is:
checking that c-ares is good and recent enough... no
configure: error: c-ares library defective or too old

but: curl-7.18.1 + c-ares-1.5.1 is ok

-- 
dengminwen_at_gmail.com