Some problems have been reported when compiling ClamAV's built-in LLVM with recent
    C++ compiler releases. These problems may be avoided by installing and using
    an external LLVM system library. To configure ClamAV to use LLVM that is installed
    as a system library instead of the built-in LLVM JIT, use following: 
    
	$ ./configure --with-system-llvm=/myllvm/bin/llvm-config
	$ make
	$ sudo make install
    The argument to --with-system-llvm is optional, indicating the path name of
    the LLVM configuration utility (llvm-config). With no argument to --with-system-llvm,
    ./configure will search for LLVM in /usr/local/ and then /usr.
    
Recommended versions of LLVM are 3.2, 3.3, 3.4, 3.5, and 3.6. Some installations have
    reported problems using earlier LLVM versions. Versions of LLVM beyond 3.6 are not
    currently supported in ClamAV.
Cisco 2018-02-28