Add unconditional ItemDefinitionGroup in quake3.vcxproj to define DLL_ONLY
for all configurations, disabling QVM interpreter/JIT in favour of DLLs.
Fix vm_x86.c: VM_Compile was outside the #ifndef DLL_ONLY guard while
VM_CallCompiled was inside it, causing a duplicate symbol link error.
Extend the guard to cover VM_Compile as well.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
