Include <cstdlib> on macos for getenv

[agamache]

Building vulkan.cppm on macOS fails after was removed from vulkan.hpp in #2344 since the macOS version calls getenv to read the DYLD_LIBRARY_PATH environment variable.

[CLAassistant]

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[M2-TE]

Thanks for catching that! Could you adjust snippets/includes.hpp instead of the generated file and then run the generator?

Also, could you test whether substituting getenv with std::getenv allows it to compile without including the additional header? The import std is a bit inconsistent about what it exports and e.g. std::exit is exported, whereas exit is not.

[dsvensson]

@M2-TE Yep, changing to std::getenv also works.

[asuessenbach]

@dsvensson That is, this PR can be closed without merging?