Migrate to manual ELF map model

[pqlx]

As of now we use LD_PRELOAD in order to inject our library. This method is very limited. We can't attach to running processes and only target dynamically linked binaries.

An alternative might be to simply call the ld.so dlopen method, but this also has caveats:

• Only dynamically linked binaries have ld.so mapped
• the dlopen method is often not exported, and we can't always locate it

The best method would be to simple use ptrace and /proc/<pid>/mem to manually map the library .so into the address space. We'd basically write our own ptrace-backed dlopen.