With GCC 11.2 and GNU ld 2.38, I get the following link errors:
/usr/bin/ld: CMakeFiles/sigh.dir/src/smime.cpp.o:(.bss+0x0): multiple definition of `util::ccp'; CMakeFiles/sigh.dir/src/milter.cpp.o:(.bss+0x0): first defined here
/usr/bin/ld: CMakeFiles/sigh.dir/src/smime.cpp.o:(.bss+0x1): multiple definition of `util::mlfipriv'; CMakeFiles/sigh.dir/src/milter.cpp.o:(.bss+0x1): first defined here
With GCC 11.2 and GNU ld 2.38, I get the following link errors: