Cannot run testsuite

[jdoubleu <hi@jdoubleu.de>]

Hi,

I'm currently trying to run the newlib testsuite on my linux host. 
Unforunately, it looks like the tests cannot be compiled (by DEJAGNU).

I've followed the steps in 
https://sourceware.org/git/?p=newlib-cygwin.git;a=blob;f=newlib/README;h=97890b9d20ca0ac9f206d7a2334d55a3d7052289;hb=HEAD#l470 
to setup and configure my environment.

I'm getting the following stack trace when I run `make check`:
```
$ make check
...
make[1]: Entering directory '/path/to/newlib-cygwin/build'
Found expect: expect
Found runtest: runtest
/path/to/newlib-cygwin/build/testsuite
WARNING: Couldn't find tool init file
Test run by jdoubleu on Mon Mar 21 16:27:27 2022
Target is x86_64-pc-linux-gnu
Host   is x86_64-pc-linux-gnu

                 === newlib tests ===

Schedule of variations:
     unix

Running target unix
Using /usr/share/dejagnu/baseboards/unix.exp as board description file 
for target.
Using /usr/share/dejagnu/config/unix.exp as generic interface file for 
target.
Using /path/to/newlib-cygwin/newlib/testsuite/config/default.exp as 
tool-and-target-specific interface file.
WARNING: Assuming target board is the local machine (which is probably 
wrong).
You may need to set your DEJAGNU environment variable.
Running /path/to/newlib-cygwin/newlib/testsuite/newlib.elix/elix.exp ...
Running /path/to/newlib-cygwin/newlib/testsuite/newlib.iconv/iconv.exp ...
ERROR: (DejaGnu) proc "newlib_target_compile 
/path/to/newlib-cygwin/newlib/testsuite/newlib.iconv/iconvnm.c 
/path/to/newlib-cygwin/build/testsuite/iconvnm.x executable {}" does not 
exist.
The error code is TCL LOOKUP COMMAND newlib_target_compile
The info on the error is:
invalid command name "newlib_target_compile"
     while executing
"::tcl_unknown newlib_target_compile 
/path/to/newlib-cygwin/newlib/testsuite/newlib.iconv/iconvnm.c 
/path/to/newli..."
     ("uplevel" body line 1)
     invoked from within
"uplevel 1 ::tcl_unknown $args"

                 === newlib Summary ===

make[1]: Leaving directory '/path/to/newlib-cygwin/build'
```

Building the lib (`make`) works.

I've also noticed, the docs are mentioning to run `make 
check-target-newlib` (see 
https://sourceware.org/git/?p=newlib-cygwin.git;a=blob;f=newlib/README;h=97890b9d20ca0ac9f206d7a2334d55a3d7052289;hb=HEAD#l505), 
which does not seem to exist. I could only run `check` which eventually 
runs `check-DEJAGNU`.


Best regards
-- 
🙎🏻‍♂️ jdoubleu