cmake: fix qt6 build on linux/macOS

[prg318]

There seems to currently be two issues that prevent successful fceux compilation on Linux and macOS

1. This cmake add_definitions() call is no longer necessary for Qt6 - it actually expands macros that prevent the build from working:

    add_definitions( ${Qt6Widgets_DEFINITIONS} ${Qt6Qml_DEFINITIONS} ${Qt6Network_DEFINITIONS} ${Qt6Help_DEFINITIONS} ${Qt6OpenGLWidgets_DEFINITIONS} )

Ninja will refuse to even start to build. Using "Unix Makefiles"

$ ninja -C build --verbose
ninja: Entering directory `build'
ninja: error: build.ninja:127: bad $-escape (literal $ must be written as $$)
  FLAGS = -g   $<$<AND:$<STREQUAL:$<TARGET_PROPERTY:TYPE>,EXECUTABLE>,$<...
               ^ near here

Unix Makefiles will get a little farther before failing:

cmake -B build -G "Unix Makefiles"

# ...

$ make -C build
make: Entering directory '/home/lukas/tmp/fceux/build'
[  0%] Built target fceux_autogen_timestamp_deps
[  1%] Automatic MOC and UIC for target fceux
AutoMoc: /home/lukas/tmp/fceux/src/drivers/Qt/HelpPages.h: note: No relevant classes found. No output generated.
[  1%] Built target fceux_autogen
[  1%] Generating fceux_git_info.cpp
Output File: /home/lukas/tmp/fceux/build/src/fceux_git_info.cpp
Git URL: git@github.com:TASEmulators/fceux.git
Git Rev: 1e1168db6662ce86848460b5d078e17c6dc6e2ce
Generated /home/lukas/tmp/fceux/build/src/fceux_git_info.cpp
[  1%] Automatic RCC for ../resources.qrc
[  2%] Building CXX object src/CMakeFiles/fceux.dir/fceux_autogen/mocs_compilation.cpp.o
/bin/sh: -c: line 1: syntax error near unexpected token `>'
/bin/sh: -c: line 1: `cd /home/lukas/tmp/fceux/build/src && /usr/bin/c++ -DFCEUDEF_DEBUGGER -DFCEUX_BUILD_TIMESTAMP="\"16:54:38  Apr 19 2026\"" -DHAVE_ASPRINTF
-DLUA_USE_LINUX -DQT_CORE_LIB -DQT_DBUS_LIB -DQT_DEPRECATED_WARNINGS -DQT_GUI_LIB -DQT_HELP_LIB -DQT_NETWORK_LIB -DQT_NO_DEBUG -DQT_OPENGLWIDGETS_LIB -DQT_OPENGL_LIB -DQT_QMLINTEGRATION_LIB -DQT_QML_LIB -DQT_SQL_LIB -DQT_UITOOLS_LIB -DQT_WIDGETS_LIB -DX264_API_IMPORTS -D_GNU_SOURCE=1 -D_HAS_X11 -D_HAS_XKB -D_REENTRANT
-D_S9XLUA_H -D_SYSTEM_MINIZIP -D_USE_LIBARCHIVE -D_USE_LIBAV -D_USE_X264 -D_USE_X265 -D__FCEU_QNETWORK_ENABLE__ -D__FCEU_QSCRIPT_ENABLE__ -D__QT_DRIVER__ -D__QT_UI_TOOLS__ -D__SDL__ -I/home/lukas/tmp/fceux/build/src/fceux_autogen/include -I/usr/include/qt6/QtDBus -I/usr/include/qt6/QtUiPlugin -I/home/lukas/tmp/fceux/src -I/home/lukas/tmp/fceux/src/drivers -isystem /usr/include/qt6/QtWidgets -isystem /usr/include/qt6 -isystem /usr/include/qt6/QtCore -isystem /usr/include/qt6/QtGui -isystem /usr/include/qt6/QtQml -isystem /usr/include/qt6/QtQmlIntegration -isystem /usr/include/qt6/QtNetwork -isystem /usr/include/qt6/QtUiTools -isystem /usr/include/qt6/QtOpenGLWidgets -isystem /usr/include/qt6/QtOpenGL -isystem /usr/include/qt6/QtHelp -isystem /usr/include/qt6/QtSql -isystem /usr/lib/qt6/mkspecs/linux-g++ src/CMakeFiles/fceux.dir/compiler_depend.tssrc/CMakeFiles/fceux.dir/compiler_depend.tsAND:src/CMakeFiles/fceux.dir/compiler_depend.tsSTREQUAL:src/CMakeFiles/fceux.dir/compiler_depend.tsTARGET_PROPERTY:TYPE>,EXECUTABLE>,src/CMakeFiles/fceux.dir/compiler_depend.tsBOOL:src/CMakeFiles/fceux.dir/compiler_depend.tsTARGET_PROPERTY:QT_ENABLE_QML_DEBUG>>>:QT_QML_DEBUG> -Wall -Wno-write-strings -Wno-parentheses -Wno-unused-local-typedefs -fPIC -I/usr/include -I/usr/include -I/usr/include -I/usr/include -I/usr/include -I/usr/include -I/usr/include -I/usr/include/SDL2 -I/home/lukas/tmp/fceux/src/lua/src -mno-direct-extern-access -MD -MT src/CMakeFiles/fceux.dir/fceux_autogen/mocs_compilation.cpp.o -MF CMakeFiles/fceux.dir/fceux_autogen/mocs_compilation.cpp.o.d -o CMakeFiles/fceux.dir/fceux_autogen/mocs_compilation.cpp.o -c /home/lukas/tmp/fceux/build/src/fceux_autogen/mocs_compilation.cpp'
make[2]: *** [src/CMakeFiles/fceux.dir/build.make:127: src/CMakeFiles/fceux.dir/fceux_autogen/mocs_compilation.cpp.o] Error 2
make[1]: *** [CMakeFiles/Makefile2:109: src/CMakeFiles/fceux.dir/all] Error 2
make: *** [Makefile:136: all] Error 2

2. Minizip headers were not being found. Fceux uses #include <unzip.h> instead of #include <minizip/unzip.h>, so the minizip subdirectory must be manually added to the include directives:

target_include_directories(${APP_NAME} PRIVATE ${MINIZIP_INCLUDE_DIRS}/minizip)

With these CMakeLists.txt changes in place, fceux successfully compiles on Linux (tested with Arch Linux 64) and macOS (tested with Tahoe 26.4.1)

Let me know if anyone has any comments or questions