Build rules

The following build targets are defined:

fpc_all
target that builds all units and executables as well as loaders. If DEFAULTUNITS is defined, executables are excluded from the targets.
fpc_debug
the same as fpc_all, only with debug information included.
fpc_exes
target to make all executables in EXEOBJECTS.
fpc_loaders
target to make all files in LOADEROBJECTS.
fpc_packages
target to make all packages that are needed to make the files.
fpc_shared
target that makes all units as dynamic libraries.
fpc_smart
target that makes all units as smartlinked units.
fpc_units
target to make all units in UNITOBJECTS.