Support OUT_DIR located in \\?\
path on Windows
#51
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This PR is similar to #50, but determining to use
/
vs\
based on the host OS, not the target OS.From Maximum Path Length Limitation: File I/O functions in the Windows API convert "/" to "\" as part of converting the name to an NT-style name, except when using the "\\?\" prefix as detailed in the following sections. If the OUT_DIR directory for the current build on a Windows host is prefixed with "\\?\", then
include!(concat!(…, "/…"))
does not work:couldn't read \\?\D:\a\tokio\tokio\target\debug\build\rustversion-2d44b26e828f2c8d\out/version.expr: The filename, directory name, or volume label syntax is incorrect. (os error 123)
Rustc or cargo do not have any built-in way to handle including code from OUT_DIR robustly (rust-lang/rust#75075).
Specifically for a procedural macro crate, using
target_os
like in #50 sort of works, but only because Cargo does not support cross-compiling procedural macro crates (it just ignores--target
if--package
refers to a macro). But other build systems definitely support cross-compiling proc macros, and would be broken by #50 iftarget_os
is Windows but the host is not.Closes #50.