rs274ngc_pre: store tilde expanded filename

for [DISPLAY]PROGRAM_PREFIX so expanded names will be found in
subroutine search path
ngcgui: workaround reassignment of fd2

Replace puts stderr with stdout to avoid problems when
file descriptor 2 is reassigned by embedding axis app.

Original puts stderr can be restored when the inadvertent
loss of stderr is solved
pickconfig: avoid error attempting to create link

for a nonexisting target