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This has been tried before. One of the results is autoconf. At the end of the day, it's probably less painful to just bootstrap some saner interfaces if you really need them. The POSIX C API is just as standardized and exposes more than the shell interfaces.
That assumes you're targeting systems with a local compiler toolchain. A valid assumption for autotools itself, but "having a C compiler available" isn't a requirement of POSIX. (POSIX merely standardizes the interface that such a toolchain should present, if one is available.) I reiterate my example: the install.sh for the Linux edition of VMWare Workstation. Its job is to take an arbitrary machine running a desktop…
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