Fix up makefile .NOTPARALLEL heuristics so that linear building is only enforced if no object folder set and the "all" target is run. Rename library "ConfigDescriptor.c" file to "ConfigDescriptors.c" to ensure that object filenames are unique.

LUFA/Build/lufa.sources.in

@@ -75,7 +75,7 @@ LUFA_SRC_USB         := $(LUFA_ROOT_PATH)/Drivers/USB/Core/$(ARCH)/Device_$(ARCH
                         $(LUFA_ROOT_PATH)/Drivers/USB/Core/$(ARCH)/USBInterrupt_$(ARCH).c    \
                         $(LUFA_ROOT_PATH)/Drivers/USB/Core/$(ARCH)/EndpointStream_$(ARCH).c  \
                         $(LUFA_ROOT_PATH)/Drivers/USB/Core/$(ARCH)/PipeStream_$(ARCH).c      \
-                        $(LUFA_ROOT_PATH)/Drivers/USB/Core/ConfigDescriptor.c                \
+                        $(LUFA_ROOT_PATH)/Drivers/USB/Core/ConfigDescriptors.c               \
                         $(LUFA_ROOT_PATH)/Drivers/USB/Core/DeviceStandardReq.c               \
                         $(LUFA_ROOT_PATH)/Drivers/USB/Core/Events.c                          \
                         $(LUFA_ROOT_PATH)/Drivers/USB/Core/HostStandardReq.c                 \