all echo helpers are used as logging functions with output to go to the
terminal. when used in functions that are designed to return a string
though the message printed would get incorrectly captured.
the previous fix done in e3a987d977 was
stupidly flawed; somehow my testing led me to mistakenly believe that
was adequate, but retesting proves that it was not.
here we create a new FD #3 linked to stdout to output the messages on,
which testing shows works as I had actually intended it.
e.g. here:
```
Foo () { if [ "$1" = "a" ]; then printf "foo\n"; else printf "error\n"; fi; }
```
we get:
```
~$ Foo a
foo
~$ Foo b
error
~$ XX="$(Foo a)"
~$ echo "${XX}"
foo
~$ XX="$(Foo b)"
~$ echo "${XX}"
error
```
and as demonstrated, "error" got incorrectly captured by in the variable
whereas here:
```
exec 3>&1
Foo () { if [ "$1" = "a" ]; then printf "foo\n"; else printf "error\n" >&3; fi; }
```
it is different in the last case:
```
~$ XX="$(Foo b)"
error
~$ echo "${XX}"
```
the error successfully makes it to the terminal, and the variable is an
empty string (with a newline automatically printed).
Gbp-Dch: Short
c54cc2c497