Split CC to make sure we get the correct basename of the compiler

[isuruf]

See the test for an example where basename of CC value fails.

[FFY00]

Hum, I think this might be a little bit trickier.

There isn't really a spec for the CC env var, though I think the de facto standard is what make defines.
https://www.gnu.org/software/make/manual/html_node/Implicit-Variables.html

The issue is that make expands the commands like a shell, which allows use quotes, eg. CC="'this path/contains spaces!/my cursed compiler'" --some-arg.

This patch does not take quoting into account. I would expect the example I presented to work.
The current implementation does not support quoting anyway, so we could possibly merge this without that. But if we are changing the handling to align with the behavior of common build systems, we probably should make it work as expected.

Also, simply splitting on spaces also does not take into account that spaces might be escaped, eg. CC=this\ path/contains\ spaces!/my\ cursed\ compiler --some-arg, so it will break things.

I think we really need to expand the text to arguments.
Here's my naive implementation: https://gist.github.com/FFY00/0029d3001b384ff974360cd6c69b39f8

[isuruf]

Also, simply splitting on spaces also does not take into account that spaces might be escaped, eg. CC=this\ path/contains\ spaces!/my\ cursed\ compiler --some-arg, so it will break things.

getting the runtime library option might break, but compilers with spaces in them is already broken in distutils.
For eg: CC='"this\ path\ compiler" --some-arg' python setup.py build_ext doesn't work
neither does CC='this\ path\ compiler --some-arg' python setup.py build_ext

[FFY00]

Looks like the state is worse than what I was expecting then 😅

I am not sure if this is the right fix, though I would probably tend to yes.

@jaraco what do you think?

[jaraco]

I initially thought I wasn't going to have an opinion on the PR, but then I looked at the change, and had much of the same reaction as FFY00. I'd like not to introduce broken support for parsing the CC var with respect to spaces... and in particular, I'd like not to use .split(' ') unless the space character is defined as being an exclusive delimiter. In other words, while distutils may not support space-separated paths currently, I'd like not to add behavior that further reduces compatibility for such paths.

[isuruf]

Thanks @FFY00 and @jaraco