fix LLVM not using current top level src dir (#30)

Reviewed-on: https://git.bixed.xyz/Bix/eden/pulls/30
Co-authored-by: Esther1024 <lizzie@bixed.xyz>
Co-committed-by: Esther1024 <lizzie@bixed.xyz>

CMakeModules/FindLLVM.cmake

@@ -19,7 +19,7 @@ if (LLVM_FOUND AND LLVM_Demangle_FOUND AND NOT TARGET LLVM::Demangle)
     target_include_directories(LLVM::Demangle INTERFACE ${LLVM_INCLUDE_DIRS})
     # prefer shared LLVM: https://github.com/llvm/llvm-project/issues/34593
     # but use ugly hack because llvm_config doesn't support interface library
-    add_library(_dummy_lib SHARED EXCLUDE_FROM_ALL src/yuzu/main.cpp)
+    add_library(_dummy_lib SHARED EXCLUDE_FROM_ALL ${CMAKE_SOURCE_DIR}/src/yuzu/main.cpp)
     llvm_config(_dummy_lib USE_SHARED demangle)
     get_target_property(LLVM_LIBRARIES _dummy_lib LINK_LIBRARIES)
     target_link_libraries(LLVM::Demangle INTERFACE ${LLVM_LIBRARIES})