While MacOS doesn't natively support the alias attribute, let's support
it with TCC anyway. This means we need to make a decision if the
string in the alias attribute is decorated or not due to the implicit
underscore on MacOS. To make life easier we decide that it's the C name,
i.e. without underscore, and so TCC needs to emit alias names with
underscore handling.
Irrespective of that the test case needs to deal with the underscore
itself for __asm__ renaming which is always requiring the assembler name.
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