How to properly manage php reqire-paths

Question

Please consider the following folder structure:

webroot
|_config
| |_config.php
|_public
| |_MyMainEntryPoint.php
|_src
  |_inc
  | |_DatabaseProcedures.php
  |_objects
  | |_MyFancyObject.php
  |_SomeComponentA.php
  |_SomeOtherComponentB.php

Imagine, that config.php contains the code to connect to the database, DatabaseProcedures.php contains wrappers around the stored procedures in the database I want to use from my website and MyFancyObject.php defines a class that wraps data returned by one of the stored procedures.

SomeComponentA.php might be used by MyMainEntryPoint.php, while I temporarily have placed SomeOtherComponentB.php where i placed it to do some sneaky debugging. Both components use the MyFancyObject and both need to access the database. (Naturally, the database procedures need to rely on config.php)

I need to sprinkle a generous amount of require_once into most of the files to resolve all names of functions and classes. The paths I had to specify had me scratching my head.

From here I gather, that the paths I need to give depend on the location of the main executing script. So in the case of directly browsing to SomeOtherComponentB.php this would be the src-Folder. So my links would be thus:

SomeOtherComponentB.php:
require_once "inc/DatabaseProcedures.php";

DatabaseProcedures.php:
require_once "../config/config.php";
require_once "objects/MyFancyObject.php"

While when directly browsing to MyMainEntryPoint.php the links would be different:

MyMainEntryPoint.php:
require_once "../src/SomeComponentA.php";

SomeComponentA.php:
require_once "../src/inc/DatabaseProcedures.php";

DatabaseProcedures.php:
require_once "../config/config.php";
require_once "../src/objects/MyFancyObject.php";

Note the difference for the linking of MyFancyObject.php. I have tested both versions and each on its own works as expected.

But seriously: How is this supposed to be a behaviour benefitting the mental health of the poor sod having to deal with it?

Is there a way to tell php: Always take paths relative to the file that does the requiring / including?