BugFix: Allow usage of clang+mingw with zlib

[seppeon]

Specify library name and version: lib/1.0

Without this change the following occurs:

libpng/1.6.39: RUN: cmake -G "Ninja" -DCMAKE_TOOLCHAIN_FILE="C:/Users/David/.conan2/p/b/libpn0015fee6450cb/b/build/Release/generators/conan_toolchain.cmake" -DCMAKE_INSTALL_PREFIX="C:/Users/David/.conan2/p/b/libpn0015fee6450cb/p" -DCMAKE_MACOSX_BUNDLE="OFF" -DCMAKE_POLICY_DEFAULT_CMP0091="NEW" -DCMAKE_BUILD_TYPE="Release" "C:\Users\David\.conan2\p\b\libpn0015fee6450cb\b\src"

-- Using Conan toolchain: C:/Users/David/.conan2/p/b/libpn0015fee6450cb/b/build/Release/generators/conan_toolchain.cmake
-- Conan toolchain: Setting BUILD_SHARED_LIBS = OFF
-- The C compiler identification is Clang 16.0.5
-- The ASM compiler identification is Clang with GNU-like command-line
-- Found assembler: C:/utils/msys64/mingw64/bin/clang.exe
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: C:/utils/msys64/mingw64/bin/clang.exe - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Conan: Target declared 'ZLIB::ZLIB'
CMake Error at C:/Users/David/.conan2/p/b/libpn0015fee6450cb/b/build/Release/generators/cmakedeps_macros.cmake:64 (message):
  Library 'zlib' not found in package.  If 'zlib' is a system library,
  declare it with 'cpp_info.system_libs' property
Call Stack (most recent call first):
  C:/Users/David/.conan2/p/b/libpn0015fee6450cb/b/build/Release/generators/ZLIB-Target-release.cmake:24 (conan_package_library_targets)
  C:/Users/David/.conan2/p/b/libpn0015fee6450cb/b/build/Release/generators/ZLIBTargets.cmake:26 (include)
  C:/Users/David/.conan2/p/b/libpn0015fee6450cb/b/build/Release/generators/ZLIBConfig.cmake:16 (include)
  CMakeLists.txt:51 (find_package)

This occurs because in zlib, you have a detection of mingw which was not correct. It didn't identify mingw when it is used with clang. I've added a fix for this.

• I've read the contributing guidelines.
• I've used a recent Conan client version close to the currently deployed.
• I've tried at least one configuration locally with the conan-center hook activated.

[CLAassistant]

All committers have signed the CLA.

[github-actions]

🤖 Beep Boop! This pull request is making changes to 'recipes/zlib//'.

👋 @Hopobcn you might be interested. 😉

[ghost]

I detected other pull requests that are modifying zlib/all recipe:

• zlib: add version 1.3 #19342
• zlib: add version 1.3, add patch_descriptions #19274

This message is automatically generated by https://github.com/ericLemanissier/conan-center-conflicting-prs so don't hesitate to report issues/improvements there.

[seppeon]

other pull requests that are modifying zlib/all recipe

That was marked as stale before being seen to completion. It also doesn't address cygwin.

[CJCombrink]

This feels like a lot of "work" that will result in false in probably most cases (I don't have numbers but I assume mingw has quite a bit lower market share compared to gcc and msvc"
I guess it would still be better to get the short circuit behaviour compared to the old code where it returns false as soon as some condition is reached that makes it false.
I see later it is used for "if windows then _is_mingw()" but still thinks that it can do a lot lees most of the time.

[StellaSmith]

This a copy of conan-io/conan#12678 which still hasn't been merged. If you have any issues with it I recommend posting them there.

[seppeon]

Am I alright to resolve this?

[CJCombrink]

@seppeon I still think this is overly complex for a simple check. I would still recommend considering early return (see my comment here)
I am also not a deciding voice so you can resolve if you don't intend to change 👍

[conan-center-bot]

Conan v1 pipeline ✔️

All green in build 3 (681a83daf62b80e8c62cfa890a99c290cac34b57):

• zlib/1.2.13@:
  All packages built successfully! (All logs)

• zlib/1.2.12@:
  All packages built successfully! (All logs)

• zlib/1.2.11@:
  All packages built successfully! (All logs)

---

Conan v2 pipeline ❌

Note: Conan v2 builds may be required once they are on the v2 ready list

The v2 pipeline failed. Please, review the errors and note this will be required for pull requests to be merged in the near future.

See details:

Sorry, the build is only launched for Access Request users. You can request access writing in this issue.

[stale]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[github-actions]

This pull request has been automatically closed because it has not had recent activity. Thank you for your contributions.