Clang 18 on MacOS tests fail due to uncaught (but intentional) exceptions

[KrisThielemans]

We have a few tests that check if errors are thrown, e.g.

STIR/src/test/test_DateTime.cxx

Lines 105 to 114 in 209cbb6

	std::cerr << "\nThe next test should throw an error\n";
	try
	{
	Interfile_datetime_to_secs_since_Unix_epoch(DateTimeStrings("1971:02:2", "23:03:01"));
	check(false, "test ill-formed date");
	}
	catch (...)
	{
	std::cerr << "Test was ok\n";
	}

However, with clang18 on MacOS these tests all fail
https://github.com/UCL/STIR/actions/runs/10450627407/job/28935385772?pr=1489#step:12:751

Testing DICOM DateTime to epoch functionality

The next test should throw an error

ERROR: Time_Zone info '+020' does not fit DICOM standard
libc++abi: terminating due to uncaught exception of type std::runtime_error: 
ERROR: Time_Zone info '+020' does not fit DICOM standard

This is pretty weird, at catch (...) should catch all exceptions AFAIK, so this seems like a clang bug to me.

However, we know what we're throwing

STIR/src/buildblock/error.cxx

Line 62 in 209cbb6

throw std::runtime_error(msg);

So we could just as well (or even better) catch std::runtime_error.

[KrisThielemans]

Catching std::runtime_error& as in
https://github.com/UCL/STIR/pull/1496/files#diff-8edd730b56a9f4c3e9faa36d393762b837fd91893dda5e4db881a97f3a0c5cf4
does not help.
https://github.com/UCL/STIR/actions/runs/10545168824/job/29215018326#step:12:119

You should now see an error about a wrong setting for alpha

ERROR: Alpha parameter for ramp has to be between 0 and 1 but is -1
libc++abi: terminating due to uncaught exception of type std::runtime_error: 
ERROR: Alpha parameter for ramp has to be between 0 and 1 but is -1