cmake: Fix building with system minizip-ng

[ReillyBrogan]

Dolphin currently fails to build when the Linux system building it includes headers/pkgconfigs for minizip-ng built in both minizip-ng mode and legacy compat mode (the minizip API).

This is because minizip-ng is checked for in cmake however the code is not actually compatible against minizip-ng built in non-legacy mode. Until that is rectified Dolphin should just check for a pkgconfig for minizip. If the system has a pkgconfig for minizip with a version >= 4 then the system package is minizip-ng built in compat mode which is exactly what we want.

[Ferdi265]

This PR breaks the build on Arch Linux. Arch Linux ships minizip 1.3.1 (built from zlib sources) and minizip-ng 4.0.7 (built from zlib-ng/minizip-ng), which means the updated pkg-config check fails because the minizip version is not >= 4.

One solution would potentially be to check for minizip>=4 first, and fall back on minizip-ng>=4 if the first check fails.

[ReillyBrogan]

This PR breaks the build on Arch Linux

Arch Linux is building minizip-ng incorrectly. Minizip-ng can be built in legacy mode which is intended to replace the zlib minizip library. When built in this mode the pkgconfig is minizip and the library is libminizip. It can also be built with the newer API at which point the pkgconfig is minizip-ng and the library libminizip-ng.

Bizarrely the minizip-ng package on Arch Linux builds the library in legacy mode, but then uses -DMZ_LIB_SUFFIX="-ng" to force it to have the pkgconfig minizip-ng and the library libminizip-ng. This is completely incorrect, any package that searches for minizip-ng expecting to find a library with the new API will fail to build against the Arch minizip-ng package.

Dolphin is not compatible with the newer minizip-ng API, so it is incorrect for it to search for the minizip-ng pkgconfig file. That will break on any distribution that ships the old zlib minizip library and the newer minizip-ng library built correctly.

I don't know what the solution for Arch Linux is here. Since building minizip-ng under the wrong library name is an Arch-specific issue I would recommend carrying a patch to fix it on your side.

[Ferdi265]

I will report this issue on the Arch Linux bug tracker for minizip-ng, let's see if it gets fixed.

[Ferdi265]

I looked a bit into other distros that ship minizip-ng, and noticed the following:

• Debian/Ubuntu don't ship minizip-ng
• Fedora ships minizip as -ng in compat mode, minizip-ng without compat mode, version 3.x
• Alpine Linux ships minizp from zlib, minizip-ng in compat mode, version 4.x
• Arch ships minizip from zlib, minizip-ng in compat mode, version 4.x
• Gentoo ships minizip from zlib, minizip-ng with a a use flag for minizip-ng to set compat mode, warns that replacing system minizip is dangerous, version 4.x
• NixOS ships minizip from zlib, minizip-ng in compat mode, version 4.x
• FreeBSD ships minizip from zlib, minizip-ng in compat mode, version 4.x

A large majority of distros is shipping minizip-ng in the same (broken) configuration that Arch Linux is using.

Of these, Gentoo and Fedora are the only ones that build compat mode with the "minizip" pkgconfig name (and Fedora has a version that is too old). All other distros ship compat mode minizip-ng with the "minizip-ng" pkgconfig name.

I didn't look at the whole list in repology, but these are the first few I looked at.

[Ferdi265]

Arch Linux AUR dolphin-emu-git now ships a downstream patch for this that reverts this commit:

commit c0754c5870ad03d0ff46a6e34cde20fad64270fb
Author: Daniel Peukert <daniel@peukert.cc>
Date:   Fri Jul 26 08:51:52 2024 +0200

    Revert "cmake: Fix building with system minizip-ng"
    
    This reverts commit b06b816d4c29edd314e0611f4305af4c50a4c56f.

diff --git a/CMakeLists.txt b/CMakeLists.txt
index ce5d64715f..5b246b193b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -677,7 +677,7 @@ dolphin_find_optional_system_library_pkgconfig(ZSTD libzstd>=1.4.0 zstd::zstd Ex
 dolphin_find_optional_system_library_pkgconfig(ZLIB zlib-ng ZLIB::ZLIB Externals/zlib-ng)
 
 dolphin_find_optional_system_library_pkgconfig(MINIZIP
-  "minizip>=4.0.4" minizip::minizip Externals/minizip-ng
+  "minizip-ng>=4.0.4;minizip>=4.0.4" minizip::minizip Externals/minizip-ng
 )
 
 dolphin_find_optional_system_library(LZO Externals/LZO)

Seeing this patch, wouldn't preferring "minizip>=4.0.4", but falling back on "minizip-ng>=4.0.4" be better? (so, basically just reversing the order of the dependencies)

--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -677,7 +677,7 @@ dolphin_find_optional_system_library_pkgconfig(ZSTD libzstd>=1.4.0 zstd::zstd Ex
 dolphin_find_optional_system_library_pkgconfig(ZLIB zlib-ng ZLIB::ZLIB Externals/zlib-ng)
 
 dolphin_find_optional_system_library_pkgconfig(MINIZIP
-  "minizip-ng>=4.0.4;minizip>=4.0.4" minizip::minizip Externals/minizip-ng
+  "minizip>=4.0.4;minizip-ng>=4.0.4" minizip::minizip Externals/minizip-ng
 )
 
 dolphin_find_optional_system_library(LZO Externals/LZO)