This project uses git submodules and several are required for a successful build. If this tarball was NOT provided with submodules (default), some source dependencies will need to be manually added to src/3rdparty. If this project WAS provided with submodules, there are detailed dependencies (e.g. supported compilers, cmake requirements, cross-compilation) at doc/wiki/Compiling.md including platform-specific build instructions (e.g. apt-get, dnf, pacman, etc). Online documentation: https://github.com/LMMS/lmms/wiki/ Live online chat via Discord (similar to IRC): https://lmms.io/chat, Channel #programming Basic build steps: mkdir build cd build cmake ../ make sudo make install # or alternately: su -c 'make install' With the above commands an out-of-tree build is performed. You can also run "cmake ." directly in the root of source tree although this is not recommended. When performing an out-of-tree build after there's already an in-tree build, make sure to run "make distclean" before running cmake inside build-directory. If you want to use custom compiler flags simply set the environment variables CFLAGS and CXXFLAGS. After running cmake (the 3rd command above) you can see a summary of things that are going to be built into LMMS or built as plugins. Install the according libraries and development files if a certain feature is not enabled. Then remove CMakeCache.txt and run cmake again. For non-root installs, or to install to a non-standard location, provide an install prefix to cmake, using the flag: -DCMAKE_INSTALL_PREFIX= The Compilation tutorial (see docs/wiki/Compilation.md) specifically uses as "../target" for all non-root installations. This is strongly recommended if developing a patch or a feature. For root installations, can be /usr, /usr/local, /opt, etc. For most systems, the default is /usr/local. If your Qt5 installation does not reside in standard installation paths, additionally pass: -DCMAKE_PREFIX_PATH= Where is the location to Qt5 installation, usually /opt/qt5/, etc. Important wiki sections: doc/wiki/Compiling.md: Dependencies Detailed - Build Toolchain (cmake) - Compiler (gcc, clang) - Libraries (required and optional dependencies) doc/wiki/Dependencies-.md Platform-specific dependencies (Windows, Ubuntu, Fedora, macOS, etc.)