Fix import lib generation under MinGW

[kleisauke]

Override import_name after parsing the .def file, as -Wl,--output-def, in LLVM and Binutils does not include a library name in the generated .def file.

cargo-c/src/target.rs

Lines 112 to 118 in c37aec4

	} else if os == "windows" && env == "gnu" {
	// This is only set up to work on GNU toolchain versions of Rust
	lines.push(format!(
	"-Wl,--output-def,{}",
	target_dir.join(format!("{lib_name}.def")).display()
	));
	}

https://github.com/llvm/llvm-project/blob/llvmorg-19.1.6/lld/COFF/MinGW.cpp#L173-L192
https://github.com/bminor/binutils-gdb/blob/binutils-2_43_1/binutils/dlltool.c#L1813-L1872

Also bump implib while we are here, to ensure the import library works when targeting i686-pc-windows-gnu{,llvm}.

[sdroege]

CC @amyspark

[lazka]

A bit of a long shot, but we are getting crashes with the new import libs since updating to 0.10.9, see msys2/MINGW-packages#23358. I tried reverting this PR, but then it fails at dynamic link time (do I need to downgrade rust too? edit: no, doesn't help)

[lu-zero]

If you could bisect the releases to find the last one working would be great, even better if you can can make a smaller reproducer.

[lazka]

I just went back all versions, the last working version was 0.10.4, then linking is broken in general until 0.10.9, but then things crash at runtime.

[lazka]

Since the last working importlib is much simpler than the broken one, my guess is that #404 could be related

[lu-zero]

Can you please compare the two outputs and tell me what changed?

[lazka]

I'm afraid I don't know enough about this to help much (I haven't figured out why calling liq_version() crashes for starters):

• working llvm importlib (llvm-objdump -x): https://gist.github.com/lazka/89efb6328ac4208a4fa0c67b00cfab0e
• working gnu importlib (llvm-objddump -x): https://gist.github.com/lazka/54d6225d1f14a1be5593ab1e1b265f81
• broken importlib (llvm-objdump -x): https://gist.github.com/lazka/b44f77137d90304c57eafa11a8cc7fd9

Both llvm and gnu linker result in the same crash, so I assume the linker isn't at fault.

[lazka]

I've created a (smaller) reproducer: https://github.com/lazka/cargo-c-crash

Let me know if I should create a separate issue for this.

edit: I've worked around this issue my using the toolchain's dlltool to create an importlib instead of using cargo-c

edit2: I've created a separate: #443