This looks like it's really testing the host's (cross-)build environment. That seems useful, but it's not the same as testing the installation itself, e.g., a test could invoke cc to compile this file or something similar and verify that it succeeded. Should we do both? Is there some reason this test on its own is sufficient?

In D53831#1229841, @markj wrote:

This looks like it's really testing the host's (cross-)build environment. That seems useful, but it's not the same as testing the installation itself, e.g., a test could invoke cc to compile this file or something similar and verify that it succeeded. Should we do both? Is there some reason this test on its own is sufficient?

The point of this test is to check that I got the definitions right, as we do them manually. We could actually use compiler builtins for the various sys/$ARCH/include files to directly grab the types from the C compiler, but we don't. So the point is to check if what I added to the headers matches what the compiler thinks the type sizes and ranges should be. As we use the same compiler for cross-building as we install on the target, I don't see why adding another set of tests would add more certainty.