Arch linux (and others?) workaround for global variables defined multiple times in different files

[RTimothyEdwards]

At least in Arch linux, and probably others, the linker stage fails because gcc is configured to define "-fno-common" by default, and so it becomes illegal to declare a global variable of the same name in more than one C file that are going to be linked into the same object file.

The workaround is to add

set(CMAKE_C_FLAGS "-fcommon") set(CMAKE_CXX_FLAGS "-fcommon")

to CMakeLists.txt.

The real fix would be to set -fno-common to force the compiler error and then fix all the instances where global variables have been defined more than once in files being linked together.

---Tim

[belohoub]

I confirm, that this is an issue in the last Fedora release (32)