Add CURL_USE_SYSROOT_LIBZ variable to automatically link zlib in sysroot

[cntrump]

For the cross-platform compilation environment, zlib is already in sysroot.
In this case, is it possible to directly specify the link parameter -lz?

example: cmake -G Ninja -DCURL_USE_SYSROOT_LIBZ=ON ...

[vszakats]

Is it correct that you'd like to override the zlib found automatically by CMake to one that's necessary for your cross-target?

If so, have you tried this method?:

-DZLIB_INCLUDE_DIR=<custom-sysroot>/include
-DZLIB_LIBRARY=<custom-sysroot>/lib/libz.a

[cntrump]

Is it correct that you'd like to override the zlib found automatically by CMake to one that's necessary for your cross-target?

If so, have you tried this method?:

-DZLIB_INCLUDE_DIR=<custom-sysroot>/include
-DZLIB_LIBRARY=<custom-sysroot>/lib/libz.a

I encountered this problem when compiling the apple universal version, because there is only libz.tbd and no libz.a. Use -lz to link to libz.tbd correctly.

[vszakats]

Would this work in your case to spec the .tbd?:

-DZLIB_LIBRARY=/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/lib/libz.tbd

(replace with your custom full path)

[cntrump]

Would this work in your case to spec the .tbd?:

-DZLIB_LIBRARY=/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/lib/libz.tbd

(replace with your custom full path)

Works, thanks !