Experimental cygwin host support

[Berrysoft]

I have built cargo targeting MSYS2(cygwin) successfully, and found it needs some patches. This is the tracking issue.

• Add cygwin support socket2#568
• Bump prodash (unifying bytesize version) and other dependencies GitoxideLabs/gitoxide#1953
• Is it possible to continue maintain version 0.2? rust-random/getrandom#653
• SIGSEGV on exit on cygwin curl/curl#17262

[jeremyd2019]

the plan is to wait for the last patch here to be merged & released, and then do a PR to update all the dependencies in Cargo.lock/Cargo.toml at once?

[Berrysoft]

Yes. Just waiting for socket2.

[jeremyd2019]

Can you provide for a cargo novice a patch that would let me try to build cargo on Cygwin? I know there is a way to replace a crate with a reference to git which should work for socket2 but I don't know how to do that or rustix required updates (I tried but it kept fighting me over wanting 0.x instead of 1.x)

[Berrysoft]

OK.

diff --git a/Cargo.toml b/Cargo.toml
index 8348c65bb..edb893c1a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -49,7 +49,7 @@ flate2 = { version = "1.1.1", default-features = false, features = ["zlib-rs"] }
 git2 = "0.20.0"
 git2-curl = "0.21.0"
 # When updating this, also see if `gix-transport` further down needs updating or some auth-related tests will fail.
-gix = { version = "0.71.0", default-features = false, features = ["blocking-http-transport-curl", "progress-tree", "parallel", "dirwalk"] }
+gix = { version = "0.72.0", default-features = false, features = ["blocking-http-transport-curl", "progress-tree", "parallel", "dirwalk"] }
 glob = "0.3.2"
 handlebars = { version = "6.3.1", features = ["dir_source"] }
 hex = "0.4.3"
@@ -255,7 +255,7 @@ cargo-test-support.workspace = true
 gix = { workspace = true, features = ["revision"] }
 # When building Cargo for tests, a safety-measure in `gix` needs to be disabled
 # to allow sending credentials over HTTP connections.
-gix-transport = { version = "0.46.0", features = ["http-client-insecure-credentials"] }
+gix-transport = { version = "0.47.0", features = ["http-client-insecure-credentials"] }
 same-file.workspace = true
 snapbox.workspace = true

@@ -276,3 +276,6 @@ all-static = ['vendored-openssl', 'curl/static-curl', 'curl/force-system-lib-on-

 [lints]
 workspace = true
+
+[patch.'crates-io']
+socket2 = { git = "https://github.com/rust-lang/socket2.git", branch = "v0.5.x" }

Apply the patch and run cargo update.

[BrianInglis]

Local patch applied by Cygwin OpenSSL maintainer to test release; see Test: openssl 3.0.16-2, mingw64-{i686,x86_64}-openssl-3.0.16-2 and
openssl and libcurl issue with cargo

[mati865]

Have you confirmed Cargo links to OpenSSL DLL? There are some flags that rustc might use to avoid depending on system shared objects:

cargo/Cargo.toml

Lines 272 to 276 in 8d17219

	[features]
	vendored-openssl = ["openssl/vendored"]
	vendored-libgit2 = ["libgit2-sys/vendored"]
	# This is primarily used by rust-lang/rust distributing cargo the executable.
	all-static = ['vendored-openssl', 'curl/static-curl', 'curl/force-system-lib-on-osx', 'vendored-libgit2']

[jeremyd2019]

Yes, it was a bit of a mess getting everything to link in my hack "cross-compile" configuration but it did finally work:

PATH="/cygdrive/v/rust/w:/cygdrive/d/test/msys64/clang64/bin:$PATH" \
PKG_CONFIG_SYSROOT_DIR="v:/cygllvm/cygwin64" \
PKG_CONFIG="$(cygpath -w /usr/bin/pkgconf.exe)" \
LIBGIT2_NO_VENDOR=1 \
OPENSSL_DIR="$(cygpath -w /usr)" \
OPENSSL_LIB_DIR="$(cygpath -w /usr/lib)" \
OPENSSL_STATIC=0 \
DESTDIR="$(cygpath -w "$PWD/build-Cygwin/dest-rust")" \
python x.py install --stage 2

and having an exe wrapper curl-config.exe in v:/rust/w (since /usr/bin/curl-config on Cygwin is a shell script)

$ llvm-readobj --coff-imports /usr/bin/cargo | grep Name:
  Name: cyggcc_s-seh-1.dll
  Name: cygcrypto-3.dll
  Name: cygcurl-4.dll
  Name: cygwin1.dll
  Name: cyggit2-1.9.dll
  Name: cygssl-3.dll
  Name: KERNEL32.dll