Undefined reference to 'zlibng_version'

[Techokami]

Tried compiling the latest git repo on Fedora 42, and for some reason it's dying here:

[ 20%] Linking CXX static library ../../lib/librpbase.a
[ 22%] Built target rpbase
[ 22%] Linking CXX shared library ../../lib/libromdata.so
/usr/bin/ld: ../../lib/../src/librpbase/CMakeFiles/rpbase.dir/img/RpPng.cpp.o: in function `LibRpBase::RpPng::zlib_version_string()':
RpPng.cpp:(.text+0x355): undefined reference to `zlibng_version'
collect2: error: ld returned 1 exit status
make[2]: *** [src/libromdata/CMakeFiles/romdata.dir/build.make:2279: lib/libromdata.so.7.0] Error 1
make[1]: *** [CMakeFiles/Makefile2:2702: src/libromdata/CMakeFiles/romdata.dir/all] Error 2
make: *** [Makefile:166: all] Error 2
techokami@markv:~/GITS/rom-properties/build$ 

Something about zlibng? Not sure how to massage the code into compiling since I'm not a C++ person.

[GerbilSoft]

Looks like Fedora transitioned to zlib-ng. rom-properties' bundled version of zlib is also zlib-ng (for e.g. Windows), but it's built in compatibility mode (libz.so.1). Fedora's zlib-ng might be built in "native" mode (libz.so.2), so something is confusing it. EDIT: The change proposal says it's also built in compatibility mode: https://fedoraproject.org/wiki/Changes/ZlibNGTransition

I'll have to set up a Fedora VM later this week to determine a fix. For now, you can add -DUSE_INTERNAL_ZLIB=1 to the CMake line as a workaround. This will compile the built-in zlib-ng with static linking.