[fpc-devel] Makefiles updated

[Peter Vreman]

The Makefiles in the fpc tree now generate the units (*.ppu, *.o) in a
separate directory. Now it is possible to build for example i386-linux,
sparc-linux and powerpc-linux units in a single source tree.

When you already have a tree with build *.ppu files you need to run 'make
distclean' first to clean all ppu files.

It also has impact for -Fu lines in fpc.cfg and the commandline. Those now
need to point to the units/<cpu>-<os>/ (units/<os> for go32v2 and emx)
directory.

Example:

-Fu~/fpc/rtl/linux

now becomes:

-Fu~/fpc/rtl/units/i386-linux

or more generic:

-Fu~/fpc/rtl/units/$fpccpu-$fpctarget