Define the ENABLE_JIT macro through Autoconf
Add Autotools plumbing for FTL JIT enabling.
Add Automake plumbing for FTL JIT support - adding files to the build and using LLVM cflags and libs as necessary.
Enable the LLVM headers inclusion for the GTK platform.
Add 'automatical' FTL JIT enabling for the GTK port on supported architectures.
Add <cstring> inclusion in FTLAbbreviations header for using std::strlen.
Check for llvm-config, gather its version and check that it's at least 3.4.