I'm currently experimenting with compiling rdfind for Cygwin, and one of
the testcases is failing because std::runtime_error is expected to
result in the compiled program exiting with a non-zero return code,
but on Cygwin, it just seems to cause the program to terminate with a
zero return code.

I've attached a simple test case.  Compare the output on Cygwin...

    $ ./test.sh
    + cat
    + g++ test.cc
    + [[ -x a.exe ]]
    + ./a.exe
    + rc=0
    + ((  rc == 0  ))
    + echo 'Unexpected zero return code from execution'
    Unexpected zero return code from execution
    + exit 1

...with the output from one of my Debian boxes...

    $ ./test.sh
    + cat
    + g++ test.cc
    + [[ -x a.exe ]]
    + [[ -x a.out ]]
    + ./a.out
    terminate called after throwing an instance of 'std::runtime_error'
      what():  Test error
    ./test.sh: line 21: 566327 Aborted                 ./a.out
    + rc=134
    + ((  rc == 0  ))
    + echo 'Expected non-zero return code received: 134'
    Expected non-zero return code received: 134
    + exit 0

I'm not massively familiar with C++, so I could well be missing
something obvious, but this seems like an unexpected difference between
Cygwin and other *nix platforms.  Is this a Cygwin bug, or am I doing
something wrong?

cygcheck -srv output attached as well, from a minimal sandbox system I
used to confirm the issue wasn't just my environment.