Added x86 support

[neox41]

I've added support for x86. I've tested both x86 and x64 BOFs compiled with MSVC and they worked.

[Iamgublin]

case IMAGE_REL_I386_DIR32:*P = (*P + S); break; is incorrect. should change to:

case IMAGE_REL_I386_REL32: add32(P, S + SymOffset - (PBYTE)P - 4); break;   
case IMAGE_REL_I386_DIR32: *P = (*P + SymOffset + S); break;

https://github.com/llvm/llvm-project/blob/6bf66d839f1386c06e19a3621c02c8fc6a14f94f/lld/COFF/Chunks.cpp#L146