llvm-mingw
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mstorsjo
LLVM MinGW does not include zlib headers and library
This is simple. All MinGW GCC distributions I have tried includes zlib. It seems like LLVM MinGW does not. Although I could just include zlib or miniz as an additional project dependency, it would be nice if LLVM MinGW were a simple drop-in replacement and included zlib.
Counterargument: A bundled zlib can easily get outdated, leading to missing critical security fixes.
I had a specific experience about this with Krita: We were updating our dependencies in response to a certain zlib CVE, but due to some configuration mishaps, Qt ended up linking to another zlib (I suspect it was the one that comes with the mingw-builds toolchain, which at the time was already quite outdated) instead of our updated ones. We almost didn't catch that -- I only found out because I happened to be trying local builds with llvm-mingw and the configuration failed.
Ok. That's fair. In that case, we should at least list the libs that are not included in LLVM MinGW that are included in the GCC distributions (if such a list does not exist already). I have a feeling that zlib may not be the only one missing.
This toolchain doesn't come with any preinstalled libraries, aside from libffi, which is used by python. You'll have to source everything yourself.
FWIW, I'm not entirely decided here...
In general, it wasn't my experience that mostly mingw distributions come with zlib bundled. But I had a look at mingw-builds (from https://sourceforge.net/projects/mingw-w64/files/Toolchains%20targetting%20Win64/Personal%20Builds/mingw-builds/, nowadays at https://github.com/cristianadam/mingw-builds/releases), and I can see that indeed, zlib seems to be bundled there. Those toolchains seem to have a bunch of other libraries/toolkits bundled too, like tcl/tk, expat, etc, but they're sorted in a subdirectory opt, possibly only used as dependencies for some tools and not meant for others to use. Within the main x86_64-w64-mingw32/lib directory, I could only find a small number of libraries that weren't present in my toolchains - libcharset.a, libiconv.a and libz.a.
I also was about to point out that e.g. Debian/Ubuntu provided cross compilers don't come with any zlib bundled, but I did see that nowadays (since 2016 apparently, i.e. not since forever, but apparently for some time), there's a separate package available for them, with zlib for mingw targets. So I guess it can be considered available there too (but not automatically/totally bundled - I hadn't ever run into it, probably since I haven't known about it and installed it).
If searching for other similar Debian/Ubuntu packages, named -mingw-w64-dev, https://packages.ubuntu.com/search?keywords=mingw-w64-dev&searchon=names&suite=kinetic§ion=all, I found a handful, which essentially seem to be libgcrypt and its dependencies, GNU Pth interface, win-iconv and zlib.
For more context, can you point out which toolchain distributions you've used, that had zlib as a default available library bundled with the toolchain?
Technically it would be quite easy to include zlib - it's not a very problematic library. If it were to be included, do you think it should be available in both shared+static form, or static only to avoid surprises for people who might end up linking it in automatically?
The libffi as @longnguyen2004 mentions isn't available installed in the general include/lib directory and isn't meant for others to use, it's only built as part of the python install for LLDB.
But overall I share @alvinhochun's sentiment here; the toolchain should generally provide the platform itself only, while the user is responsible for third party libraries built on top of it. In general, I don't think the toolchain should start bundling any commonly used utility libraries that the user may want to use. Zlib itself might be small and common enough to be tolerable, but I don't want this to slide further into bzip2, xz, libiconv, etc.
For more context, can you point out which toolchain distributions you've used, that had zlib as a default available library bundled with the toolchain?
I primarily use MInGW distro by niXman and it includes zlib. However, I took out some time to carefully check some other distros and here is what I found.
| Distro | zlib included |
|---|---|
| https://nuwen.net/mingw.html | yes |
| https://jmeubank.github.io/tdm-gcc/ | no |
| https://github.com/skeeto/w64devkit | no |
| https://github.com/niXman/mingw-builds-binaries | yes |
| https://winlibs.com/ | no |
| https://sourceforge.net/projects/mingw-w64/ | yes |
| https://gcc-mcf.lhmouse.com/ | yes |
Technically it would be quite easy to include zlib - it's not a very problematic library. If it were to be included, do you think it should be available in both shared+static form, or static only to avoid surprises for people who might end up linking it in automatically?
Well, after reading what @alvinhochun wrote, I am convinced that toolchains should not include third party libraries. If you do want to include zlib, then just a static lib should be fine IMO. If you decide otherwise, that's fine too (probably better 😊).
Well, after reading what @alvinhochun wrote, I am convinced that toolchains should not include third party libraries. If you do want to include zlib, then just a static lib should be fine IMO. If you decide otherwise, that's fine too (probably better 😊).
Thanks for the survey! With that in mind, that it's not a common thing that one in general can rely on being present, I think it's best for us to just stick to the current status quo of not including zlib here.