Just for posterities sake, in case you need to compile pgplot on debian,
the makefile created does not point to the right location for
the includes for
pndriv.o : /usr/include/png.h /usr/include/pngconf.h /usr/include/zlib.h /usr/include/zconf.h
so you correc them to that.
also the problem with tcl and tk is due to the lack of
libtk.so -> libtk8.5.so.0
libtcl.so -> libtcl8.5.so.0
once i added them the compilation was fine.
however i then found pgplot in non-free repository so this is not neccesary.