I compiled php7 as below
./configure --enable-bcmath --with-bz2 --enable-calendar --enable-exif --enable-dba --enable-ftp --with-gettext --enable-mbstring --with-mcrypt --with-mhash --enable-pcntl --with-pspell --enable-shmop --enable-soap --enable-sockets --enable-sysvmsg --enable-sysvsem --enable-sysvshm --enable-wddx --enable-zip --with-readline --with-curl --enable-debug --enable-maintainer-zts --enable-pthreads --prefix=/usr --with-config-file-path=/etc --prefix=/usr
# sudo make
sudo make throws following error
/usr/bin/ld: ext/curl/.libs/interface.o: undefined reference to symbol 'CRYPTO_set_id_callback@@OPENSSL_1.0.0' //lib/x86_64-linux-gnu/libcrypto.so.1.0.0: error adding symbols: DSO missing from command line collect2: error: ld returned 1 exit status make: *** [sapi/cli/php] Error 1
make: *** [sapi/cli/php] Error 1