Get valgrind (it's free) and do the above, like so:
configure --disable-shared --enable-symbols
make CFLAGS_WARNING=-DPURIFY ; # add -DPURIFY
valgrind ./tclsh ; # may neeed TCL_LIBRARY set
You should find that the TclFSNormalizeAbsolutePath
(IIRC) is listed as a leaker (you may find many, but
that's one). It always happens when the function that
calls it next goes into FsUpdateCwd.