Hi all! I have available prebuilt 64-bit binaries. I would be happy to provide the link to download my prebuilt binaries (that I use with Abyss under CentOS 7.5).
However, should you wish to build your own from source, you can do so using the following configure command:
./configure --prefix=/opt/php73 --with-mysqli --with-gd --enable-fpm --enable-mbstring --with-mysql --with-mcrypt --enable-sockets --with-penssl --with-gmp --with-gettext --with-pdo_mysql
Then when you run 'make install' after running 'make', PHP (v7.3 in this case) will install in the /opt/php73 directory. This method is good when you have differing version of PHP installed for different web sites (as I do). Please note, too, that the necessary header files will also need to be present when building from source.