fix(sys): work around missing UNC path support in MSVC

`std::fs::canonicalize` always converts paths to UNC on Windows.
However, a plenty of software lacks support for this naming convention,
notably Microsoft's C/C++ Compiler.

`dunce::canonicalize` is a commonly used solution that picks the most
compatible path representation on Windows and calls `fs::canonicalize`
on any other platform.

Author: bavshin-f5

Cargo.lock

@@ -20,6 +20,7 @@ rust-version.workspace = true
 bindgen = "0.71"
 cc = "1.2.0"
 duct = { version = "0.13.7", optional = true }
+dunce = "1.0.5"
 flate2 = { version = "1.0.28", optional = true }
 # Disable non-ASCII domain names support in ureq. We don't need it for any
 # of the 4 domains the buildscript interacts with.

nginx-sys/Cargo.toml

@@ -60,7 +60,7 @@ const NGX_CONF_OS: &[&str] = &[
 /// NGINX in a subdirectory with the project.
 fn main() -> Result<(), Box<dyn StdError>> {
     let nginx_build_dir = match std::env::var("NGX_OBJS") {
-        Ok(v) => PathBuf::from(v).canonicalize()?,
+        Ok(v) => dunce::canonicalize(v)?,
         #[cfg(feature = "vendored")]
         Err(_) => vendored::build()?,
         #[cfg(not(feature = "vendored"))]
@@ -170,10 +170,7 @@ fn parse_includes_from_makefile(nginx_autoconf_makefile_path: &PathBuf) -> Vec<P
         .parent()
         .expect("makefile path has no parent")
         .parent()
-        .expect("objs dir has no parent")
-        .to_path_buf()
-        .canonicalize()
-        .expect("Unable to canonicalize makefile path");
+        .expect("objs dir has no parent");
 
     includes
         .into_iter()
@@ -185,7 +182,9 @@ fn parse_includes_from_makefile(nginx_autoconf_makefile_path: &PathBuf) -> Vec<P
                 makefile_dir.join(path)
             }
         })
-        .collect()
+        .map(dunce::canonicalize)
+        .collect::<Result<Vec<_>, _>>()
+        .expect("canonicalize include paths")
 }
 
 /// Collect info about the nginx configuration and expose it to the dependents via