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Many times when I run configure, I get this message:

checking minix/config.h usability... no
checking minix/config.h presence... no
checking for minix/config.h... no

configure runs without errors or warnings, but getting a message every time and not understanding what it means is slightly disturbing. I did some research and know that Minix is a light-weight unix-like OS, but not sure why configure checks the presence of this particular file.

What does minix/config.h do and what does configure use it for?

cozyconemotel
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1 Answers1

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./configure scripts look for minix/config.h to determine whether they're building on Minix, or not. The test is defined in specific.m4. Autoconf sets a couple of variables up when it detects Minix, that's all it does — of course, specific builds may then react differently, but that depends on the project being built, not on Autoconf.

As you've noticed, the test itself is harmless. ./configure scripts are generated in such a way that they can run on a wide variety of platforms; that's the whole point in fact. So they include a bunch of feature detection that's only relevant for a subset of platforms, and which you'll see "failing" most of the time; but there's no reason to worry about it.

Stephen Kitt
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    Thank you so much for clarifying. I kept thinking there had to be some other use because the thought of configure scripts that run on every machine dedicating three lines of log just for Minix was hard for me to take in.. – cozyconemotel Dec 22 '16 at 10:58