... On modern Unix derivatives there exists a nifty mechanism usually called dynamic linking/loading of Dynamic Shared Objects (DSO) which provides a way to build a piece of program code in a special format for loading it at run-time into the address space of an executable program. ... The idea is simple: When installing Apache the configure 's make install procedure installs the Apache C header files and puts the platform-dependent compiler and linker flags for building DSO files into the apxs program....