[fpc-pascal] Compiler bootstrapping?

[Tiziano_mk]

I am not sure to understand this text from FPC FAQs item no. 3.
Can someone explain better?

Bootstrapping:
FPC requires a suitable set of binutils (AS,AR,LD), gmake and a
commandline compiler. New architectures/OSes are crosscompiled. GPC
bootstraps via a suitable version of GCC, and requires a full set of
binutils, flex, bison, gmake, a POSIX shell and libtool.

thanks
tiziano