Build all stable LLVM targets

[junlarsen]

As discussed in #932 I have enabled LLVM to build all stable targets.

[saudet]

While we're at it, let's also include your code for issue #935? It looks alright.

[saudet]

Apart from the experimental targets, it looks like the following functions are not actually defined:

   Creating library jniLLVM.lib and object jniLLVM.exp
jniLLVM.obj : error LNK2001: unresolved external symbol "void __cdecl LLVMInitializeXCoreAsmParser(void)" (?LLVMInitializeXCoreAsmParser@@YAXXZ)
jniLLVM.obj : error LNK2001: unresolved external symbol "void __cdecl LLVMInitializeNVPTXAsmParser(void)" (?LLVMInitializeNVPTXAsmParser@@YAXXZ)
jniLLVM.obj : error LNK2001: unresolved external symbol "void __cdecl LLVMInitializeNVPTXDisassembler(void)" (?LLVMInitializeNVPTXDisassembler@@YAXXZ)
jniLLVM.dll : fatal error LNK1120: 3 unresolved externals

Do we just disable them for all targets?

[junlarsen]

Yeah, it seems like those targets don't export those functions for some reason. We could either omit the initialization functions for those targets entirely or we just omit those three functions manually (example gist)