Prompt to install build tools (gcc/phpize/etc) if missing

[asgrim]

Add a pre-check to ensure relevant toolchain is available for building.

By default, PIE should prompt to see if the user wants to install any missing tools. Example for Ubunutu apt install gcc make autoconf libtool bison re2c pkg-config; check for package names in yum/apk/etc too depending on the system. If we can't detect how to install the tools (or we are running non-interactively), just write a warning to the user that the tools are missing, and they should be installed.

However, this checking behaviour should be disabled with a flag, if provided, as some people may not want it.