MSVC's `link.exe` automatically finds `__cdecl` C functions (which are
decorated with a leading underscore by the compiler) when they are
mentioned in a `.def` file without the leading underscore. This is an
[under-documented feature][1] of MSVC's `link.exe`. C++Builder's
`ilink32.exe` doesn't do this, and thus needs the name-translation in
the `.def` file. Then `implib.exe` needs to be told to re-add it.
(The Clang-based `bcc32c.exe` doesn't implement the [`-vu` or `-u-`][2]
options to skip adding the leading underscore to `__cdecl` C function
names, so this is the only way to have things work with non-underscored
export names in the DLLs.)